Yeast two-hybrid screening identifies binding partners of human Tom34 that have ATPase activity and form a complex with Tom34 in the cytosol.
In the accompany paper (Mukhopadhyay, A., Avramova, L. V. and Weiner, H., Arch. Biochem. Biophys.), it was shown that Tom34, a previously proposed putative translocase of the mitochondrial outer membrane, binds to the mature region of a precursor protein and appears to be a cytosol protein. Here Tom34 was used as bait in a yeast two-hybrid screening to search for its potential binding partners. Two of the identified proteins were the ATPase-related valosin-containing protein (VCP) and the lysosomal H(+)-transporting ATPase member M (ATP6M). Tom34 was found primarily in the cytosol while VCP and ATP6M were found in the cytosol as well as in nonmitochondrial organelles. Tom34 formed a approximately 400-kDa complex with them in the cytosol. Tom34 was found to possess a weak ATPase activity that did not change when associated with VCP. The tetratricopeptide repeat (TPR) motif region of Tom34 (residue 201-256) was responsible for binding to the other proteins. Tom34 appears not to be a member of the mitochondrial outer membrane translocase family but might function as a chaperone-like protein during protein translocation.
Yang
Chun-Song
CS
Biochemistry Department, Purdue University, West Lafayette, Indiana 47907, USA.
Weiner
Henry
H
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism*; D003001:Cloning, Molecular; D003600:Cytosol / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D006367:HeLa Cells; D006801:Humans; D006868:Hydrolysis; D007525:Isoelectric Focusing; D008099:Liver / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D002352:Carrier Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011994:Recombinant Proteins; C108485:TOMM34 protein, human; D000251:Adenosine Triphosphatases