Cytosolic factors mediate protein insertion into the peroxisomal membrane.
Following in vitro translation of the 22 kDa peroxisomal membrane protein (Pmp22p), gel filtration analysis of the post-ribosomal supernatant revealed that Pmp22p forms two complexes. Complex I is of high molecular weight, results in a crosslinking product of 80 kDa, and by co-immunoprecipitation with anti-TCP1 antibody was identified as TRiC. In complex II Pmp22p was crosslinked to a yet unknown polypeptide of 40 kDa (P40). This complex exhibited much higher efficiency to insert Pmp22p into the peroxisomal membrane compared to complex I. In a model we suggest that newly synthesized Pmp22p is first bound to TRiC before being transferred to P40 which may function as a cytosolic Pmp22p receptor.
Pause
B
B
Biochemie-Zentrum, Universität Heidelberg, Germany.
Diestelkötter
P
P
Heid
H
H
Just
W W
WW
D000818:Animals; D000906:Antibodies / Q000276:immunology; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins / Q000276:immunology; D002850:Chromatography, Gel; D003600:Cytosol / Q000737:chemistry / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D007425:Intracellular Membranes / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008099:Liver / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D008830:Microbodies / Q000378:metabolism*; D008869:Microtubule-Associated Proteins; D008930:Mitochondria, Liver / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D051381:Rats; D017208:Rats, Wistar; D012156:Reticulocytes / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases; D056427:t-Complex Genome Region
D000906:Antibodies; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; C489785:PXMP2 protein, human; C079231:Pxmp2 protein, rat; C533304:TCP1 protein, human; C533316:Tcp1 protein, rat; C116196:PPP1R11 protein, human; D044767:Ubiquitin-Protein Ligases; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins