Peroxisome Research

Pex11 in spotlight

2015-05-31T23:27:00.000+02:00

Open European Peroxisome Meeting 2014 (OEPM2014) in Neuss (Germany)

2014-06-21T15:05:00.000+02:00

4th Open European Peroxisome Meeting. (OEPM2014)

Official Website : http://oepm2014.de/index.php

Dates : September, 9-11, 2014

Registration Deadline : July, 7, 2014

Registration Link : http://oepm2014.de/registration.php

Registration Fees : (covers participation, accommodation and food)

250 EUR (double room occupancy)
350 EUR (single room occupancy)

Location :
Commundo Tagungshotel Neuss
Neuss, Germany

Organizer :

Prof. Dr. Ralf Erdmann

Institute of Physiological Chemistry
Department of System Biochemistry
Ruhr-University Bochum.
Germany.

Conference on peroxisome biology - ITN PerFuMe Kick off conference

2013-11-25T11:53:00.000+01:00

For more details Visit the website - http://www.itn-perfume.eu/events/8/kick-off-conference

Dates - December 1-4, 2013

Schedule

Start: 01-12-2013 (18:00:00)
End: 04-12-2013 (15:00:00)

Address -

Hampshire Plaza
Laan Corpus den Hoorn 300
9728 JT Groningen
The Netherlands

Organizers -
Prof. Dr. Ida J. van der Klei, University of Groningen
Ms Jannet Kampen
Ms Tamara Hummel

Vacancies - 12 Marie Curie Fellowships in the PERFUME Initial Training Network

2013-02-25T00:21:00.000+01:00

Peroxisomes: key to cell performance and health

The Marie Curie Initial Training Network PERFUME (PERoxisome FUnction, MEtabolism) is opening 12 Marie Curie fellowship positions for Early Stage Researchers. PERFUME is funded by the European Union Seventh Framework Programme under Grant Agreement No. 316723.

The PERFUME program is an interdisciplinary and intersectoral initial stage training network (ITN) at the interface of medicine, plant and fungal biology, devoted to understanding the principles of peroxisome biology. Peroxisomes are ubiquitous organelles that are essential in man. Relative to other organelles, still little is known on their biogenesis and function

PERFUME brings together a team comprising of top scientists from the fields of cell biology, biochemistry, genomics, proteomics, metabolomics, mathematical modeling, bioinformatics and protein structure analysis. The training schemes include specific research projects, a wide range of dedicated courses and workshops organized by the academic and industrial partners of the Network.

For more information see http://www.itn-perfume.nl.

Requirements

The positions for Early Stage Researchers are available for candidates with a research experience ≤ 4 years (counted from the diploma that gives the rights to embark in a doctoral degree). Candidates must not have resided or carried out their main activity (work, studies, etc) in the country of their host organisation for more than 12 months in the 3 years immediately prior to recruitment (short stays, such as holidays, are not taken into account). Candidates should have exceptional academic performance, subject specific skills and expertise, team working abilities and competence in written and spoken English.

Length of appointment: 3 years

Type of Contract: temporary

Starting date: between July 2013 and October 2013

Applications

The application form can be found at http://www.itn-perfume.eu/vacancies

Application deadline: 31/03/2013

Press Release - Marie Curie Initial Training Network PERFUME (Peroxisome Function Metabolism)

2013-02-25T00:11:00.000+01:00

Future European Science Leaders to Work on Cutting-edge Peroxisome Research

“Peroxisomes: Key to Cell Performance and Health”

Start of EU-funded Marie Curie Initial Training Network

PERFUME 2013-2016

Groningen, 20 February 2013 – the Marie Curie Initial Training Network PERFUME announces the start of a new multiple year research programme on Peroxisome Function Metabolism. The programme aims at providing state-of-the-art research training to 12 PhD students and 4 postdocs at the interface of medicine, plant and fungal biology. Marie Curie Initial Training Networks are highly prestigious awards funded by the European Union Seventh Framework Programme, focused on the training of the next generation of European leaders in science to solve interdisciplinary questions of global concern and to increase the European competitiveness in research and development.

PERFUME is a multi-partner Initial Training Network under the European Union programme FP7-PEOPLE-2012-ITN with a total budget of 3.9 Mio €. PERFUME is coordinated by Prof. Dr. Ida van der Klei (University of Groningen, the Netherlands). It involves an interdisciplinary consortium formed by eleven European research groups from research institutes, universities and leading companies from different industrial sectors with a running period from January 2013 until December 2016. The PERFUME fellows will be trained by a team of top scientists from the fields of cell biology, biochemistry, genomics, proteomics, metabolomics, mathematical modeling, bioinformatics and protein structure analysis. The PERFUME training program offers outstanding young scientists the opportunity to maturize in science and enhance their career prospects through high-impact socially significant research.

The PERFUME network seeks to unravel the principles of peroxisome biology. Peroxisomes are small organelles that occur in nearly all cells, from a simple baker’s yeast cell to humans and crop plants. Peroxisomes are crucially important for cell vitality, and babies with inherited peroxisome defects generally die rather early. Despite 60 year of worldwide research, the atlas of peroxisome functions is still far from complete. Unraveling these requires extensive further analysis. Enhancing peroxisome knowledge is relevant for medicine, agriculture and biotechnology. For the first time, PERFUME combines expertise from different disciplines and sectors that cuts across historically separated fields of peroxisome biology.

The PERFUME objectives will be achieved by a diverse, well–balanced and interdisciplinary consortium with well-recognised experience in peroxisome biology and biotechnology. These include the University of Groningen (Prof. Dr. Ida J. van der Klei), the University Medical Centre Groningen (Prof. Dr. Barbara M. Bakker), the Amsterdam Medical Centre, Amsterdam (Dr. Hans R. Waterham), the European Molecular Biology Laboratory in Hamburg (Dr. Matthias Wilmanns), The University of Exeter (Prof. Dr. M. Schrader), The University of Stavanger (Prof. Dr. S. Reumann), the Ruhr University Bochum (Prof. Dr. Ralf Erdmann), the Ruprecht-Karls-University Heidelberg (Dr. D. Devos), Evitraproteoma AB (Dr. D. Molina, Sweden), Metabolomic Discoveries GmbH (Dr. Nicolas Schauer, Germany) and Lifeglimmer GmbH (Prof. Dr. Ir. Vitor A.P. Martins dos Santos, Germany).

For further information visit our website www.itn-perfume.eu

(Note - posted for academic purpose.)

Forthcoming Peroxisome meetings 2011

2011-07-26T17:31:00.001+02:00

GFPD Family and Scientific Conference

July 31 – August 2, 2011

Omaha, Nebraska

Program

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Gordon Research Conference

Cell-Cell Fusion

In Sex, Life, Development and Disease

August 7-12, 2011

University of New England

Biddeford, ME

8 August 2011, Monday

9:10 am - 9:40 am

Randy Schekman (UC Berkeley, USA)

"Mechanism of Sorting and Traffic of Peroxisomal Proteins from the ER"

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International Conference on Plant Peroxisome Research

satellite meeting to Plant Biology 2011

August 11, 2011

Hilton Minneapolis, Minneapolis, Minnesota, USA

Full program

17 talks, 21 posters and 42 registered researchers..

online registration is available till 11 August 2011

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FEBS workshop 2011

Plant Organellar Signalling

from algae to higher plants

Primošten, Croatia

31 August - 3 September 2011

Full program

Peroxisome related talks -

31 August - Wednesday

Session 2 - ORGANELLE BIOGENESIS AND FUNCTION

12:00 –12:15

OEF18 is a novel calcium binding protein at peroxisomes and chloroplasts

Simon Stael (Uni. Vienna, Austria)

14:00 –14:15

The PEX11 family: Deciphering a key player of peroxisomal proliferation

Friedrich Kragler (MPI-Golm, Germany?)

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Special Interest Group meeting on Peroxisome biology

Saturday 10 September, 10:00 to 17:15

Part of the Special Interest symposia during EMBO meeting 2011 Vienna, Austria.

Organisation: Ida van der Klei, Marten Veenhuis

12 talks by European peroxisome researchers.

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9th international conference on AAA proteins

6-10 November 2011

Kumamoto, Japan

09 November 2011

09:00 - 09:30

Ralf Erdmann (Ruhr-Univ. Bochum, Germany)

Functional role of the yeast AAA-peroxins Pex1p and Pex6p in peroxisome biogenesis

09:30 - 10:00

Yukio Fujiki (Kyushu Univ, Japan)

To be announced

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New player in ER-Peroxisome field

2011-07-24T23:08:00.001+02:00

Peroxisomes proliferate by growth and division as well as they can arise de novo from Endoplasmic reticulum. In yeast, it was recently shown that most PMPs transit to peroxisomes via ER. In mammalian cells, Pex16 and Pex3 are known to target peroxisomes via ER. But the key players involved in this ER-peroxisome transport are still poorly known.

The new study published in PNAS identifies Sec16B as factor essential for Pex16 export from ER to peroxisomes.

Sec16B is involved in the endoplasmic reticulum export of the peroxisomal membrane biogenesis factor peroxin 16 (Pex16) in mammalian cells

Yonekawa et al, Online published before print on 18 july 2011, PNAS

Sec16B(Sec16S) is a vertebrate specific isoform which is less extensively studied than the Sec61A(Sec16L). Comparing the sizes, Sec16B is almost half the size that of Sec16A and these proteins are able to form heteromeric complexes too.

This study found that, overexpression of Sec16B results in reduced number of peroxisomes and ER localization of Pex16 and Pex3. On the other hand, siRNA mediated knockdown of Sec16B results in tubulated peroxisomes, ER localization of pex16 and degradation of Pex3 by Ubiquitin proteasomal system. Authors also characterized different regions of Sec16B and found that C-terminal of Sec16B which differs from Sec16A, is required for its function in peroxisome biogenesis. Peroxisome vesicle formation from ER is known to be independent of COPII vesicle budding. Sec16A as well as Sec16B are involved formation of COPII vesicles and are targeted to ERES(ER Exit Sites). Authors meticulously shown that, stretch of Sec16B responsible for its recruitment to ERES is not required for its peroxisome related function.

Further reading

Cell-free sorting of peroxisomal membrane proteins from the endoplasmic reticulum

PNAS, May 2011

A vesicle carrier that mediates peroxisome protein traffic from the endoplasmic reticulum

PNAS, December 2011

Urban planning of the endoplasmic reticulum (ER): How diverse mechanisms segregate the many functions of the ER

BBA Mol Cell Research, in press

Glycosome related abstracts - KMCB 2011

2011-04-29T16:09:00.001+02:00

Kinetoplastid Molecular Cell Biology Meeting

Meeting Date: April 8-12, 2011

Woods Hole, MA

Leishmania donovani receptor-cargo protein complexes form in the cytosol and dock at glycosomal protein Peroxin14, modulating its conformation.

The Leishmania donovani glycosomal protein peroxin 14 hydrophobic region is necessary for membrane association

Extra-Glycosomal Localization of Trypanosoma brucei Hexokinase 2

A compensatory mutant of Leishmania major lacking ether lipids exhibits normal growth and neomycin resistance

The role of L. Mexicana Arginase in host infection

New high impact articles - Novel family of stress-protective proteins and pexophagy

2011-04-17T20:14:00.000+02:00

A novel family of dehydrin-like proteins is involved in stress response in the human fungal pathogen Aspergillus fumigates

Sak Hoi et al

MBoC in Press, published April 13, 2011

Authors identified two novel proteins DprA and DprB which are important for peroxisome functioning. Both of these proteins when fused to eGFP localize to peroxisomes and cytosol. Dpr mutants exhibit altered catalase levels and impaired peroxisomal beta-oxidation.

Damaged peroxisomes are subject to rapid autophagic degradation in the yeast Hansenula polymorpha

Zutphen et al

Autophagy (Impact Factor - 6.829)

Volume 7, Issue 8 August 2011

Authors identified the massive peroxisome degradation process resembling both micro and macro-pexophagy using Pex3 fused with temperature sensitive degron sequence at N-terminus.

New review about Mammalian peroxisomal ABC transporters

2011-04-15T00:19:00.001+02:00

Mammalian peroxisomal ABC transporters: from endogenous substrates to pathology and clinical significance
Kemp S et al
British Journal of Pharmacology
Impact Factor - 5.2
Wiley Online Library

Accepted article published online on 14 April 2011

Latest peroxisome articles from high impact journal "The Plant Cell"

2011-04-13T11:02:00.000+02:00

Two latest articles about plant peroxisomes from journal "The Plant Cell"
Impact Factor - 10.679

Identification of Novel Plant Peroxisomal Targeting Signals by a Combination of Machine Learning Methods and in Vivo Subcellular Targeting Analyses
Lingner T et al.
First Published on April 12, 2011

Arabidopsis ABERRANT PEROXISOME MORPHOLOGY9 Is a Peroxin That Recruits the PEX1-PEX6 Complex to Peroxisomes
Shino Goto et al.
First Published on April 12, 2011

Treat for the eyes

I thought of introducing an additional feature to this research blog by making it semi-informal.
I would extend the blogposts about peroxisomes with suitable interesting and sometimes non-scientific material like pictures suiting the mood of article or useful links, pictures, video etc.

Stunning photography by my friend Rakesh Chandode

"Beauty of plants"

Link to other galleries of eye-catching pics by Rakesh Chandode on National Geogrpahic
http://ngm.nationalgeographic.com/myshot/gallery/150984
http://ngm.nationalgeographic.com/myshot/gallery/251405

Postdoctoral position at The University of Stavanger, Norway

2011-04-02T18:20:00.000+02:00

Title of project - “Molecular analyses of peroxisome-mediated pathogen defense mechanisms in Arabidopsis”
University of Stavanger
Faculty of Science and Technology,
Department of Mathematics and Natural Science,
The Centre for Organelle Research (CORE.)

Funding Agency - Norwegian Research Council (project 204822/F20)

Salary - NOK 448.400 per annum

Date of beginning fellowship - July 1, 2011

Closing date for applications - April 26th, 2011

Link -
http://www.uis.no/about_us/vacant_positions/article35393-88.html

A Novel micropexophagy specific protein 'Atg35' identified in Pichia pastoris

2011-03-29T23:29:00.001+02:00

Atg35, a micropexophagy-specific protein that regulates micropexophagic apparatus formation in Pichia pastoris
Nazarko VY et al,
Autophagy, Volume 7, Issue 4, April 2011, Pages 375 - 385

Pexophagy can occur by two distinct pathways termed as macropexophagy and micropexophagy. In Pichia pastoris, methanol to ethanol shift causes macropexophagy while methanol to glucose shift results in peroxisome degradation by micropexophagy.

During micropexophagy, peroxisome cluster is first step-wisely surrounded by engulfing vacuole and requires a specific component called micropexophagy apparatus (MIPA) for the complete engulfment and subsequent degradation.

Using Atg28 as a bait in Yeast two hybrid screen, Authors identified a novel protein Atg35 which is micropexophagy-specific and important for efficient MIPA formation. Overexpression or deletion of this protein abolished MIPA formation without affecting other autophagic pathways. It is also observed that Atg28 bridges the interaction between Atg17 and Atg35. Authors also characterized the novel site PNS (Perinuclear Structure) where Atg35 is recruited by Atg17.

More pexophagy related recent literature -

CCZ1, MON1 and YPT7 genes are involved in pexophagy, the Cvt pathway and non-specific macroautophagy in the methylotrophic yeast Pichia pastoris
Cell Biol Int. 2011 Feb

The phosphoinositide 3-kinase Vps34p is required for pexophagy in Saccharomyces cerevisiae
Biochem J. 2011 Jan

A yeast MAPK cascade regulates pexophagy but not other autophagy pathways
J Cell Biol. 2010 Apr

Novel yeast Peroxin identified - Pex34

2011-03-26T13:30:00.002+01:00

The Peroxin Pex34p Functions with the Pex11 Family of Peroxisomal Divisional Proteins to Regulate the Peroxisome Population in Yeast
Robert J. Tower, Andrei Fagarasanu, John D. Aitchison, and Richard A. Rachubinski
Molecular Biology of the Cell 2011, doi:10.1091/mbc.E11-01-0084

Authors have characterized the protein encoded by YCL056c gene. Currently the protein is annotated as "Protein of unknown function" in Saccharomyces Genome Database and described as green fluorescent protein (GFP)-fusion protein localizing to the cytoplasm in a punctate pattern. (schematic image from SGD)

Authors have renamed the protein as Pex34 which is an integral peroxisomal membrane protein. Pex34 is found to be positive regulator of peroxisome population under constitutive as well as inducing conditions. Pex34 deletion led to reduced number and enlarged peroxisomes whereas overexpression led to increased peroxisome number. Authors also found interaction of pex34 with itself and other Pex11 family peroxins using yest two hybrid analysis. Notably Pex34 interacts with Fis1 but not with Vps1.

Note - Recently Pex33 was identified from Neurospora crassa
Identification of PEX33, a novel component of the peroxisomal docking complex in the filamentous fungus Neurospora crassa
Managadze D et al.

New Peroxisome related method

2011-03-25T12:09:00.000+01:00

Isolation of mRNAs Encoding Peroxisomal Proteins from Yeast Using a Combined Cell Fractionation and Affinity Purification Procedure
Zipor G, Brocard C, Gerst JE.

Methods in Molecular Biology, Vol. 714, 2011;714:323-333.
RNA Detection and Visualization
Edited by Jeffrey E. Gerst

PhD position: Control of peroxisome abundance in metabolic diseases & cancer

2011-03-10T12:17:00.000+01:00

Employer : Institute of Cell Biology, ETH Zurich, Switzerland
Website : http://www.cell.biol.ethz.ch
Last date of application : April 15, 2011

Interested applicants should email their CV, short statement of research interests(half page), and names of 2 referees by email to: Werner.kovacs@cell.biol.ethz.ch
Or by using Online application link

Our research interests are on the genetic and biochemical mechanisms underlying the control of peroxisome abundance in metabolic diseases and cancer. Peroxisomes are highly versatile and dynamic organelles whose number, size and function are vastly dependent on the cell type and growth conditions. The abundance of peroxisomes within a cell is dynamically controlled by environmental cues and (patho)physiological conditions. We apply a wide range of experimental cues technologies (e.g. live-cell imaging, RNAi-screening, functional genomics, proteomics, metabolomics) and model disease states in the mouse.

The successful candidate will be enrolled in the Ph.D. Program of the Life Science Zurich Graduate School. The position is located in Science City, the Life Science Campus of ETH Zurich. The research campus offers state-of-the-art facilities for advanced light and electron microscopy, high-throughput, image-based RNAi screening, quantitative proteomics, functional genomics, and computational analysis of large data-sets.

For further scientific information please contact: werner.kovacs@cell.biol.ethz.ch (http://www.cell.biol.ethz.ch/research/krek/group_members/kovacsw/index).

Dr. Werner Kovacs
ETH Zürich
Institute of Cell Biology
Schafmattstrasse 18, HPM F39
CH-8093 Zürich, Switzerland

New Paper - Study on Pex5 ancillary binding site for SCP2

2011-03-08T12:44:00.000+01:00

The Peroxisomal Targeting Signal 1 in sterol carrier protein 2 is autonomous and essential for receptor recognition
Williams CP et al.
BMC Biochemistry 2011, 12:12
Published: 4 March 2011

Brief Summary - Authors studied the second, ancillary receptor-cargo binding site in Pex5 for the PTS1 protein SCP2 distinct from the PTS1 itself. Point mutation in Pex5 were done to check the effects on Pex5-SCP2 binding which was found to be moderately reduced in binding assays but the effect was not visible using in vivo localisation assays. Authors conclude that the second binding site in Pex5 is not essential for at least SCP2 indicating PTS1 is alone sufficient for its peroxisomal targeting.

Mutations within the ancillary SCP2 binding site of Pex5p do not impair peroxisomal import

PTS1 of SCP2 is essential and sufficient for peroxisomal targeting

(Thanks to Biomedcentral BMC, Open Access Publisher for the open access policy)

2012 Peroxisome talks

2011-01-24T12:18:00.000+01:00

Keystone Symposia
Cell Biology of Virus Entry, Replication and Pathogenesis
March 26 - 31, 2012

March 30, Friday
Talk -
Peroxisomes, MAVS and Innate Immunity
Jonathan C. Kagan, Boston Children's Hospital, USA

Link - http://www.keystonesymposia.org/Meetings/ViewMeetings.cfm?MeetingID=1167

Peroxisome related events in 2011

2011-01-10T15:01:00.002+01:00

EMBO Conference
Protein Transport Systems
Structures, mechanisms and medical aspects
16 - 20.04.2011, Santa Margherita di Pula, Italy

17.04.2011
20:30 - 21:00
Ralf Erdmann
The peroxisomal protein import machinery

19.04.2011
17:00 - 17:30
Adabella van der Zan
lluminating the peroxisomal biogenesis pathway
_____________________________________________________________________

9th international conference on AAA proteins
6-10 November 2011, Kumamoto Japan

9 November 2011

09:00 - 09:30

Ralf Erdmann (Ruhr-Univ. Bochum, Germany)

Functional role of the yeast AAA-peroxins Pex1p and Pex6p in peroxisome biogenesis

09:30 - 10:00

Yukio Fujiki (Kyushu Univ, Japan)

To be announced

Peroxisomes - Alzheimer's Disease and Hepatitis

2011-01-09T19:39:00.000+01:00

Hepatitis B Virus Regulatory HBx Protein Binds to Adaptor Protein IPS-1 and Inhibits the Activation of Beta Interferon
Journal of Virology, January 2011
Kumar M et al.
From the group of Prof. B. L. Slagle
Baylor College of Medicine, Texas
Brief Description -

IPS1 is also known as MAVS (mitochondrial antiviral signaling) protein. Last year it was discovered that MAVS subpopulation also resides on peroxisomes and is responsible for rapid but transient type I-interferon independent antiviral gene expression(Dixit et al, Cell, 2009). It was known that Hepatitis A and Hepatitis C viral proteins target IPS1 to inactivate host innate immune response. This paper establishes that Hepatitis B viral protein HBx also modulates host signalling by targeting IPS1. Since IPS1 also resides on peroxisomes, there arises the possibility of HBV acting at this organelle.

Plasmalogen synthesis is regulated via alkyl-dihydroxyacetonephosphate-synthase (AGPS) by amyloid precursor protein (APP) processing and is affected in Alzheimer’s disease
Grimm et al.
Journal of Neurochemistry, January 2011 (Accepted Article)
Brief Description -

Alkyl-dihydroxyacetonephosphate-Synthase (AGPS) is a PTS2 containing peroxisomal protein involved in ether lipid biosynthesis. Plasmalogen synthesis is also defective in PBDs (Peroxisome Biogenesis Disorders). This paper shows that APP protein in Alzheimer disease regulates AGPS.

Role of FADH2/NADH flux ratio in peroxisome evolution..!

2010-12-13T19:20:00.000+01:00

Dr. Dave Speijer from University of Amsterdam has authored an Hypothesis article under "Insights & Perspectives" in BioEssays Journal.

"Oxygen radicals shaping evolution:

Why fatty acid catabolism leads to peroxisomes while neurons do without it -

FADH2/NADH flux ratios determining mitochondrial radical formation were crucial for the eukaryotic invention of peroxisomes and catabolic tissue differentiation"

According to Dr.Speijer, F/N Flux ratio (ratio of electrons passing through FADH2 and NADH) was the critical factor which led to acquisition of membrane bound organelle peroxisome that became specialized in beta oxidation of VLCFA.

The hypothesis is corroborated with experimental evidence from other researchers that this flux ratio determines the level of oxygen radicals produced. So cell tries to keep the F/N ratio to minimum to avoid dangerous burst of oxygen radicals by leakage of electrons in mitochondria.

So according to this kinetic model, though peroxisomal metabolism of fatty acids is less energy efficient(less ATP yield) than mitochondrial pathway, peroxisomes contribute in dissipating Excess FADH2 arising from VLCFA metabolism.

FADH2 is generated in first step of beta-oxidation. in peroxisomes, FADH2 doesn't go through Electron Transport Chain(Thus less ATP yield!), but rather utilized by catalase for Hydrogen peroxide detoxification.

Post-doctoral position

2010-11-29T11:54:00.000+01:00

Postdoctoral Fellow in the Cell Biology of Peroxisomes

to study the molecular mechanisms of peroxisome inheritance in the model organism, Saccharomyces cerevisiae
Link to the Advertisement on Naturejobs.com

in the lab of Prof.Richard Rachubinski,
Department of Cell Biology,
University of Alberta, Canada

See Latest Review by Prof. Rachubinski group
Molecular mechanisms of organelle inheritance: lessons from peroxisomes in yeast
Nature Reviews Molecular Cell Biology, September 2010

New insights into peroxisome function and an in vivo peroxisomal trafficking assay

2010-10-12T15:05:00.004+02:00

Peroxisomal pipecolate pathway involved in L-lysine catabolism in brain

Therapeutic modulation of cerebral L-lysine metabolism in a mouse model for glutaric aciduria type I.
Sauer et al
Department of General Paediatrics,
Division of Inborn Metabolic Diseases, University Children’s Hospital, Hiedelberg.
Published in journal Brain (A journal of neurology) published online: October 4, 2010
Impact factor of journal BRAIN - 9.49

L-lysine catabolism proceeds via mitochondrial saccharopine pathway or peroxisomal pipecolate pathway. Human L-pipecolate oxidase(PIPOX) is a peroxisomal enzyme carrying C-terminal PTS1 motif (KAHL). Peroxisome Biogenesis Disorder patients lacking peroxisomes or defective in matrix protein import, lack L-pipecolate oxidase activity. Type I Glutaric aciduria patients have genetic defect in glutaryl-CoA dehydrogenase, which leads to accumulation of neurotoxic metabolites. In this paper, Authors used animal model of this disease(gcdh deficient mice) to study the effects of dietary interventions and underlying mechanism of their therapeutic effect. They observed that in brain, Lysine catabolism occurs mainly by peroxisomal L-pipecolate pathway whereas in hepatic cells, it occurs via mitochondrial pathway.

This paper demonstrates that peroxisomes play an important role in brain, by preventing the accumulation of toxic metabolites in L-lysine catabolism. Clofibrate treatment in these mice could further lower the glutaric acid accumulation, which shows that peroxisomal pipecolate pathway could be targeted to recover the defects in mitochondrial enzyme glutaryl-CoA dehydrogenase. Why brain cells prefer action of PIPOX for lysine degradation over saccharopine pathway remains to be better understood.

Peroxisomes as a tool to study motor proteins in cellular traffic

Probing intracellular motor protein activity using an inducible cargo trafficking assay
Kapitein et al.
From the group of Prof. Casper Hoogenraad, Erasmus MC, Rotterdam
Published in Biophysical Journal (Cell Press). Impact Factor - 4.39

Various motor proteins mediate cellular movements on the cytoskeleton network. Kinesins and dyneins are generally involved in long range transport over microtubule network while myosin motors mediate short range movement over actin network. Though the knowledge about how individual motor proteins work was deduced from in vitro studies. In vivo functional dynamics of the motor proteins is still elusive owing to diversity and complexity of the various motor proteins involved in single event. Kapitein et al. report in this paper, an inducible cargo trafficking assay which can be employed in live cells with great control. The assay is based on peroxisomes, so called in vivo peroxisomal trafficking assay. The assay is based on the dimerisation property of two proteins FKBP and FRB on addition of cell permeable rapalog. Rapalogs are non-immunosuppressive analogs of rapamycin which can be used conveniently in ARGENT regulated Heterodimerization Kit produced by Ariad Pharmaceuticals. Pex3 is fused to RFP(for visualisation) and FKBP, whereas the motor protein to be studied is fused to FRB. Both constructs are coexpressed in mammalian cells (in this paper, COS7 cells). Upon addition of rapalog, heterodimeraisation is induced leading to recruitment of desired motor protein to peroxisomes and initiated movement of peroxisomes. Since peroxisomes in COS7 cells are relatively immobile and clustered around nucleus. Authors observed that Kinesins induce +end directed movement of peroxisomes leading to peripheral distribution of peroxisomes. Dyneins result in -end directed movement of peroxisomes towards nucleus. As expected, myosins induce only short range movement.

Authors also did simultaneous visualization of peroxisomes and microtubules and tracked the movements. Peroxisomes where labeled with GFP using Pex26 targeting information, while microtubules were labeled with mcherry. They observed that peroxisomes often pause at microtubule intersections and resume their movement on same or another microtubule after the second microtubule gets depolymerised till the junction.

This in vivo peroxisomal trafficking assay was used by authors in another paper (Kapitein et al, Current Biology, 2010) to demonstrate that kinesins are preferred for trafficking in axons and dyneins are preferred in dendrites in hippocampal neurons. This demonstrates the this assay can be utilized to study individual motor proteins as well as combination of them.

Though this study and the assay were not designed to study peroxisome movement, but to study the properties of motor proteins. But since our knowledge about endogenous movement of peroxisomes and the motor proteins involved is scanty, so I believe that this assay can be directed for peroxisome research also.

Stories behind Nobel

2010-09-24T11:36:00.000+02:00

Christian de Duve alongwith Albert claude and George Palade received Nobel prize in physiology or medicine in 1974 "for their discoveries concerning the structural and functional organization of the cell"

de Duve discovered peroxisomes, the organelle which harbors still some more mysteries about its roles and origin. Here is the video of interview with Christian de Duve from Web of stories. Not just one or two videos but whooping 106 videos on the web of stories website.

Its so inspiring to watch him speaking on different topics. I hope every peroxisome researcher will like to listen to it.

a quote from one of the video

"I'm not a genius, I didn't invent relativity, or discover relativity, I didn't discover the double helix, I'm not a colourful personality like Francis Crick or Jim Watson, Richard Feynman and so on. So, I'm just a rather ordinary person with a slightly out of ordinary experience"

de Duve talking about family background

For next videos visit the web of stories website
http://www.webofstories.com/play/15984

Update of the week (13-20 September 2010)

2010-09-14T11:35:00.009+02:00

New Paper accepted in Hepatology (Impact Factor - 10.84)
Unconjugated bile salts shuttle through hepatocyte peroxisomes for taurine conjugation
Rembacz KP et al
From the group of Klaas Nico Faber

New accepted paper in Journal of Neuroendocrinology (Impact Factor - 3.7)
D-Aspartate Oxidase Localisation in Pituitary and Pineal Glands of the Female Pig
Yamamoto A. et al.
Brief background - DDO (D-aspartate oxidase) is a PTS1 containing peroxisomal protein.

PhD Dissertation by Anca Nenicu
Supervisor - Prof. Dr. Eveline Baumgart-Vogt
Influence of peroxisomes on development, maturation and adult functions of the testis
submitted to Justus-Liebig-Universität Gießen
pdf link
Link posted for academic purposes only. Please read the associated copyright note on the website

New Paper in PLoS One (Impact Factor - 4.351)
Deficient Liver Biosynthesis of Docosahexaenoic Acid Correlates with Cognitive Impairment in Alzheimer's Disease
Astarita G. et al.
From the group of Prof. Daniele Piomelli
Findings in Brief - peroxisomal D-bifunctional protein activity is reduced in liver leading to impaired DHA biosynthesis in Alzheimer patients.

Fig. 1 from the paper -
Overview of docosahexaenoic acid biosynthesis in liver.

ABCD1 and ABCD2 are peroxisomal membrane proteins involved in fatty acid transport.

ACOX1 and HSD17B4, are peroxisomal matrix enzymes involved in beta-oxidation functions, both have C-terminal PTS1 signal.

Review in Microbiology Monographs "Structures and Organelles in Pathogenic Protists"
The Glycosome of Trypanosomatids
By Fred R. Opperdoes

Peroxisome Research

Pex11 in spotlight

Recent articles on Pex11.

Open European Peroxisome Meeting 2014 (OEPM2014) in Neuss (Germany)

Conference on peroxisome biology - ITN PerFuMe Kick off conference

Vacancies - 12 Marie Curie Fellowships in the PERFUME Initial Training Network

Press Release - Marie Curie Initial Training Network PERFUME (Peroxisome Function Metabolism)

Forthcoming Peroxisome meetings 2011

New player in ER-Peroxisome field

Glycosome related abstracts - KMCB 2011

New high impact articles - Novel family of stress-protective proteins and pexophagy

New review about Mammalian peroxisomal ABC transporters

Latest peroxisome articles from high impact journal "The Plant Cell"

Postdoctoral position at The University of Stavanger, Norway

A Novel micropexophagy specific protein 'Atg35' identified in Pichia pastoris

Novel yeast Peroxin identified - Pex34

New Peroxisome related method

PhD position: Control of peroxisome abundance in metabolic diseases & cancer

New Paper - Study on Pex5 ancillary binding site for SCP2

2012 Peroxisome talks

Peroxisome related events in 2011

Peroxisomes - Alzheimer's Disease and Hepatitis

Role of FADH2/NADH flux ratio in peroxisome evolution..!

Post-doctoral position

New insights into peroxisome function and an in vivo peroxisomal trafficking assay

Stories behind Nobel

Update of the week (13-20 September 2010)