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In vivo time-lapse microscopy reveals that the number of peroxisomes in Saccharomyces cerevisiae cells is fairly constant and that a subset of the organelles are targeted and segregated to the bud in a highly ordered, vectorial process. The dynamin-like protein Vps1p controls the number of peroxisomes, since in a vps1Delta mutant only one or two giant(More)
Peroxisomes can arise de novo from the endoplasmic reticulum (ER) via a maturation process. Peroxisomes can also multiply by fission. We have investigated how these modes of multiplication contribute to peroxisome numbers in Saccharomyces cerevisiae and the role of the dynamin-related proteins (Drps) in these processes. We have developed pulse-chase and(More)
Peroxisomes undergo rapid, selective autophagic degradation (pexophagy) when the metabolic pathways they contain are no longer required for cellular metabolism. Pex3 is central to the formation of peroxisomes and their segregation because it recruits factors specific for these functions. Here, we describe a novel Saccharomyces cerevisiae protein that(More)
Two peroxisome targeting signals (PTSs) for matrix proteins have been well defined to date. PTS1 comprises a COOH-terminal tripeptide, SKL, and has been found in several matrix proteins, whereas PTS2 has been found only in peroxisomal thiolase and is contained within an NH2-terminal cleavable presequence. We have investigated the functional integrity of the(More)
The endocytic pathway in yeast leads to the vacuole, but resident proteins of the late Golgi, and some endocytosed proteins such as the exocytic SNARE Snc1p, are retrieved specifically to the Golgi. Retrieval can occur from both a late pre-vacuolar compartment and early or 'post-Golgi' endosomes. We show that the endosomal SNARE Pep12p, and a mutant version(More)
Turnover of damaged, dysfunctional, or excess organelles is critical to cellular homeostasis. We screened mutants disturbed in peroxisomal protein import, and found that a deficiency in the exportomer subunits Pex1, Pex6, and Pex15 results in enhanced turnover of peroxisomal membrane structures compared with other mutants. Strikingly, almost all peroxisomal(More)
Saccharomyces cerevisiae Pex3p has been shown to act at the ER during de novo peroxisome formation. However, its steady state is at the peroxisomal membrane, where its role is debated. Here we show that Pex3p has a dual function: one in peroxisome formation and one in peroxisome segregation. We show that the peroxisome retention factor Inp1p interacts(More)
The Saccharomyces cerevisiae peroxisomal membrane protein Pex11p has previously been implicated in peroxisome proliferation based on morphological observations of PEX11 mutant cells. Pex11p-deficient cells fail to increase peroxisome number in response to growth on fatty acids and instead accumulate a few giant peroxisomes. We report that mutants deficient(More)
Pex3 is an evolutionarily conserved type III peroxisomal membrane protein required for peroxisome formation. It is inserted into the ER membrane and sorted via an ER subdomain (the peroxisomal ER, or pER) to peroxisomes. By constructing chimeras between Pex3 and the type III ER membrane protein Sec66, we have been able to separate the signals that mediate(More)
A recent model for peroxisome biogenesis postulates that peroxisomes form de novo continuously in wild-type cells by heterotypic fusion of endoplasmic reticulum-derived vesicles containing distinct sets of peroxisomal membrane proteins. This model proposes a role in vesicle fusion for the Pex1/Pex6 complex, which has an established role in matrix protein(More)