Redox-sensitive homodimerization of Pex11p: a proposed mechanism to regulate peroxisomal division

• Published in: The Journal of cell biology 1996-10, Vol.135 (1), p.123-137
• Main Authors: Marshall, P.A. (University of Texas Southwestern Medical Center, Dallas, TX.), Dyer, J.M, Quick, M.E, Goodman, J.M
• Format: Article
• Language: English
• Subjects: Base Sequence; BIOCHIMIE; BIOQUIMICA; Budding; Cell Division - drug effects; Cell Division - physiology; Cell lines; Cells; Cellular biology; CISTEINA; Cross-Linking Reagents; CYSTEINE; Cysteine - physiology; Dimerization; Dimers; Fungal Proteins - analysis; Fungal Proteins - chemistry; Fungal Proteins - genetics; Fungal Proteins - physiology; Galactose - pharmacology; Gels; GENE; GENES; IMMUNOLOGIE; INMUNOLOGIA; Intracellular Membranes - chemistry; Intracellular Membranes - ultrastructure; MEMBRANAS CELULARES; MEMBRANE CELLULAIRE; Membrane Proteins - analysis; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - physiology; Microbodies - physiology; Molecular Sequence Data; Molecular Weight; Monomers; MUTACION; MUTANT; MUTANTES; MUTATION; Oleic Acid - pharmacology; Organelles; Organisms; ORGANITE CELLULAIRE; ORGANULOS CITOPLASMICOS; Oxidation-Reduction; Peroxins; Peroxisomes; Physiological regulation; Point Mutation; PROTEINAS; PROTEINE; Proteins; REACCIONES QUIMICAS; REACTION CHIMIQUE; REDUCCION; REDUCTION; REPLICACION; REPLICATION; SACCHAROMYCES CEREVISIAE; Saccharomyces cerevisiae Proteins; Succinimides; Yeasts
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.135.1.123

Pex11p (formerly Pmp27) has been implicated in peroxisomal proliferation (Erdmann, R.. and G. Blobel. 1995. J. Cell Biol. 128: 509-523; Marshall, P.A., Y.I. Krimkevich, R.H. Lark, J.M. Dyer, M. Veenhuis, and J.M. Goodman. 1995. J. Cell Biol. 129: 345-355). In its absence, peroxisomes in Saccharomyces cerevisiae fail to proliferate in response to oleic acid; instead, one or two large peroxisomes are formed. Conversely, overproduction of Pex11p causes an increase in peroxisomal number. In this report, we confirm the function of Pex11p in organelle proliferation by demonstrating that this protein can cause fragmentation in vivo of large peroxisomes into smaller organelles. Pex11p is on the inner surface of the peroxisomal membrane. It can form homodimers, and this species is more abundant in mature peroxisomes than in proliferating organelles. Removing one of the three cysteines in the protein inhibits homodimerization. This cysteine 3 replaced by alanine mutation leads to an increase in number and a decrease in peroxisomal density, compared with the wild-type protein, in response to oleic acid. We propose that the active species is the "monomeric" form, and that the increasing oxidative metabolism within maturing peroxisomes causes dimer formation and inhibition of further organelle division