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The Candida boidinii peroxisomal membrane protein Pmp30 has a role in peroxisomal proliferation and is functionally homologous to Pmp27 from Saccharomyces cerevisiae.

ABSTRACT: The mechanism of peroxisome proliferation is poorly understood. Candida boidinii is a methylotrophic yeast that undergoes rapid and massive peroxisome proliferation and serves as a good model system for this process. Pmp30A and Pmp30B (formerly designated Pmp31 and Pmp32, respectively) are two closely related proteins in a polyploid strain of this yeast that are strongly induced by diverse peroxisome proliferators such as methanol, oleate, and D-alanine. The function of these proteins is not understood. To study this issue, we used a recently described haploid strain (S2) of C. boidinii that can be manipulated genetically. We now report that strain S2 contains a single PMP30 gene very similar in sequence (greater than 93% identity at the DNA level) to PMP30A and PMP30B. When PMP30 was disrupted, cell growth on methanol was greatly inhibited, and cells grown in both methanol and oleate had fewer, larger, and more spherical peroxisomes than wild-type cells. A similar phenotype was recently described for Saccharomyces cerevisiae cultured on oleate in which PMP27, which encodes a protein of related sequence that is important for peroxisome proliferation, was disrupted. To determine whether Pmp27 is a functional homolog of Pmp30, gentle complementation was performed. PMP30A was expressed in the PMP27 disruptant of S. cerevisiae, and PMP27 was expressed in the PMP30 disruptant of C. boidinii S2. Complementation, in terms of both cell growth and organelle size, shape, and number, was successful in both directions, although reversion to a wild-type phenotype was only partial for the PMP30 disruptant. We conclude that these proteins are functional homologs and that both Pmp30 and Pmp27 have a direct role in proliferation and organelle size rather than a role in a specific peroxisomal metabolic pathway of substrate utilization.

SUBMITTER: Sakai Y

PROVIDER: S-EPMC177542 | biostudies-other | 1995 Dec

REPOSITORIES: biostudies-other

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The Candida boidinii peroxisomal membrane protein Pmp30 has a role in peroxisomal proliferation and is functionally homologous to Pmp27 from Saccharomyces cerevisiae.

Sakai Y Y Marshall P A PA Saiganji A A Takabe K K Saiki H H Kato N N Goodman J M JM

Journal of bacteriology 19951201 23

The mechanism of peroxisome proliferation is poorly understood. Candida boidinii is a methylotrophic yeast that undergoes rapid and massive peroxisome proliferation and serves as a good model system for this process. Pmp30A and Pmp30B (formerly designated Pmp31 and Pmp32, respectively) are two closely related proteins in a polyploid strain of this yeast that are strongly induced by diverse peroxisome proliferators such as methanol, oleate, and D-alanine. The function of these proteins is not und ...[more]

PMID: 7592467

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Project description:In this study we cloned CTA1, the gene encoding peroxisomal catalase, from the methylotrophic yeast Candida boidinii and studied targeting of the gene product, Cta1p, into peroxisomes by using green fluorescent protein (GFP) fusion proteins. A strain from which CTA1 was deleted (cta1Delta strain) showed marked growth inhibition when it was grown on the peroxisome-inducing carbon sources methanol, oleate, and D-alanine, indicating that peroxisomal catalase plays an important nonspecific role in peroxisomal metabolism. Cta1p carries a peroxisomal targeting signal type 1 (PTS1) motif, -NKF, in its carboxyl terminus. Using GFP fusion proteins, we found that (i) Cta1p is transported to peroxisomes via its PTS1 motif, -NKF; (ii) peroxisomal localization is necessary for Cta1p to function physiologically; and (iii) Cta1p is bimodally distributed between the cytosol and peroxisomes in methanol-grown cells but is localized exclusively in peroxisomes in oleate- and D-alanine-grown cells. In contrast, the fusion protein GFP-AKL (GFP fused to another typical PTS1 sequence, -AKL), in the context of CbPmp20 and D-amino acid oxidase, was found to localize exclusively in peroxisomes. A yeast two-hybrid system analysis suggested that the low transport efficiency of the -NKF sequence is due to a level of interaction between the -NKF sequence and the PTS1 receptor that is lower than the level of interaction with the AKL sequence. Furthermore, GFP-Cta1pDeltankf coexpressed with Cta1p was successfully localized in peroxisomes, suggesting that the oligomer was formed prior to peroxisome import and that it is not necessary for all four subunits to possess a PTS motif. Since the main physiological function of catalase is degradation of H2O2, suboptimal efficiency of catalase import may confer an evolutionary advantage. We suggest that the PTS1 sequence, which is found in peroxisomal catalases, has evolved in such a way as to give a higher priority for peroxisomal transport to peroxisomal enzymes other than to catalases (e.g., oxidases), which require a higher level of peroxisomal transport efficiency.

Dataset Information

The Candida boidinii peroxisomal membrane protein Pmp30 has a role in peroxisomal proliferation and is functionally homologous to Pmp27 from Saccharomyces cerevisiae.

Publications

The Candida boidinii peroxisomal membrane protein Pmp30 has a role in peroxisomal proliferation and is functionally homologous to Pmp27 from Saccharomyces cerevisiae.

Similar Datasets

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