cDNA cloning and characterization of a constitutively expressed isoform of the human peroxin Pex11p.

We cloned a human cDNA encoding an isoform of the peroxin Pex11p, termed Pex11pbeta, by screening of human liver cDNA library using as a probe human EST-derived, approximately 300 bp-long nucleotides showing homology to PEX11 from Candida boidinii and Saccharomyces cerevisiae. PEX11beta encoded a protein comprising 259 amino acids, with two putative transmembrane segments, showing approximately 40% identity to inducible Pex11palpha, at the amino acid sequence level. Pex11pbeta was found to be a peroxisomal protein, as assessed by colocalization with acyl-CoA oxidase, an enzyme catalyzing the first step of peroxisomal beta-oxidation system, in Pex11pbeta-expressing Chinese hamster ovary cells. PEX11beta was not induced in rats by treatment of clofibrate, a peroxisome proliferator, in contrast to PEX11alpha.