The Peroxin Pex34p Functions with the Pex11 Family of Peroxisomal Divisional Proteins to Regulate the Peroxisome Population in Yeast

TitleThe Peroxin Pex34p Functions with the Pex11 Family of Peroxisomal Divisional Proteins to Regulate the Peroxisome Population in Yeast
Publication TypeJournal Article
Year of Publication2011
AuthorsTower RJ, Fagarasanu A, Aitchison JD, Rachubinski RA
JournalMol Biol Cell
Date PublishedMar 25
PMID21441307
AbstractPeroxisomes are ubiquitous organelles involved in a diversity of metabolic processes, most notably the metabolism of lipids and the detoxification of reactive oxygen species. Peroxisomes are highly dynamic and change in size and number in response to both intra- and extracellular cues. In the yeast Saccharomyces cerevisiae, peroxisome growth and division are controlled by both the differential import of soluble matrix proteins and a specialized divisional machinery that includes peroxisome-specific factors such as members of the Pex11 protein family and general organelle divisional factors like the dynamin-related protein Vps1p. Global yeast 2-hybrid analyses have demonstrated interactions between the product of the S. cerevisiae gene of unknown function, YCL056c, and Pex proteins involved in peroxisome biogenesis. Here we show that the protein encoded by YCL056c, renamed Pex34p, is a peroxisomal integral membrane protein that acts independently and also in concert with the Pex11 protein family members Pex11p, Pex25p and Pex27p to control the peroxisome populations of cells under conditions of both peroxisome proliferation and constitutive peroxisome division. Yeast 2-hybrid analysis showed that Pex34p interacts physically with itself and with Pex11p, Pex25p and Pex27p but not with Vps1p. Pex34p can act as a positive effector of peroxisome division as its overexpression leads to increased numbers of peroxisomes in wild-type and pex34Delta cells. Pex34p requires the Pex11 family proteins to promote peroxisome division. Our discovery of Pex34p as a protein involved in the already complex control of peroxisome populations emphasizes the necessity of cells to strictly regulate their peroxisome populations to be able to respond appropriately to changing environmental conditions.

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