The Yarrowia lipolytica Gene PAY5 Encodes a Peroxisomal Integral Membrane Protein Homologous to the Mammalian Peroxisome Assembly Factor PAF-1

Gary A Eitzen,Vladimir I Titorenko,Jennifer J Smith,Marten Veenhuis,Rachel K Szilard,Richard A Rachubinski

doi:10.1074/jbc.271.34.20300

Gary A Eitzen, Vladimir I Titorenko + Show 4 more

Open Access

https://doi.org/10.1074/jbc.271.34.20300

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Abstract

Pay mutants of the yeast Yarrowia lipolytica fail to assemble functional peroxisomes. One mutant strain, pay5-1, lacks normal peroxisomes and instead contains irregular vesicular structures surrounded by multiple unit membranes. The pay5-1 mutant is not totally deficient in peroxisomal matrix protein targeting, as a subset of matrix proteins continues to localize to a subcellular fraction enriched for peroxisomes. The functionally complementing gene PAY5 encodes a protein, Pay5p, of 380 amino acids (41,720 Da). Pay5p is a peroxisomal integral membrane protein homologous to mammalian PAF-1 proteins, which are essential for peroxisome assembly and whose mutation in humans results in Zellweger syndrome. Pay5p is targeted to mammalian peroxisomes, demonstrating the evolutionary conservation of the targeting mechanism for peroxisomal membrane proteins. Our results suggest that in pay5 mutants, normal peroxisome assembly is blocked, which leads to the accumulation of the membranous vesicular structures observed.

Highlights

Eukaryotic cells have evolved a complex set of organelles, with each organelle possessing a specific complement of enzymes required for its particular metabolic role
Functional complementation of some of these mutants have identified genes encoding a varied set of proteins required for peroxisome biogenesis, including proteins required for the recognition, targeting, and translocation of PTS1-containing [12,13,14,15,16,17,18,19,20] and PTS2-containing [21,22,23] peroxisomal matrix proteins
Isolation and Characterization of the PAY5 Gene—The PAY5 gene was isolated from a Y. lipolytica genomic DNA library by functional complementation of the mutation in pay5-1 cells

Summary

Introduction

Eukaryotic cells have evolved a complex set of organelles, with each organelle possessing a specific complement of enzymes required for its particular metabolic role. This compartmentalization of biochemical functions permits a level of metabolic control unavailable to prokaryotes. Functional complementation of some of these mutants have identified genes encoding a varied set of proteins required for peroxisome biogenesis (for a recent review, see Ref.4), including proteins required for the recognition, targeting, and translocation of PTS1-containing [12,13,14,15,16,17,18,19,20] and PTS2-containing [21,22,23] peroxisomal matrix proteins. Pay5p is homologous to mammalian PAF-1 proteins, which are required for peroxisome assembly and whose mutation results in the hereditary human peroxisome assembly disorder, Zellweger syndrome [25, 26]

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