Cloning and characterization of a novel RING finger protein that interacts with class V myosins.
We have identified a novel protein (BERP) that is a specific partner for the tail domain of myosin V. Class V myosins are a family of molecular motors thought to interact via their unique C-terminal tails with specific proteins for the targeted transport of organelles. BERP is highly expressed in brain and contains an N-terminal RING finger, followed by a B-box zinc finger, a coiled-coil (RBCC domain), and a unique C-terminal beta-propeller domain. A yeast two-hybrid screening indicated that the C-terminal beta-propeller domain mediates binding to the tail of the class V myosin myr6 (myosin Vb). This interaction was confirmed by immunoprecipitation, which also demonstrated that BERP could associate with myosin Va, the product of the dilute gene. Like myosin Va, BERP is expressed in a punctate pattern in the cytoplasm as well as in the neurites and growth cones of PC12 cells. We also found that the RBCC domain of BERP is involved in protein dimerization. Stable expression of a mutant form of BERP lacking the myosin-binding domain but containing the dimerization domain resulted in defective PC12 cell spreading and prevented neurite outgrowth in response to nerve growth factor. Our studies present a novel interaction for the beta-propeller domain and provide evidence for a role for BERP in myosin V-mediated cargo transport.
El-Husseini
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Graduate Program in Neuroscience, Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
Vincent
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D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D003001:Cloning, Molecular; D019281:Dimerization; D015696:Gene Products, tat / Q000378:metabolism; D007381:Intermediate Filament Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D018995:Myosin Heavy Chains; D024701:Myosin Type V; D009218:Myosins / Q000378:metabolism; D009414:Nerve Growth Factors / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D016415:Sequence Alignment; D014157:Transcription Factors / Q000378:metabolism; D000070584:Tripartite Motif Proteins; D014407:Tumor Cells, Cultured; D044767:Ubiquitin-Protein Ligases; D015003:Yeasts
C120405:BERP; D015696:Gene Products, tat; D007381:Intermediate Filament Proteins; C513081:Myo5a protein, rat; C101826:Myo5b protein, rat; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D000070584:Tripartite Motif Proteins; C094027:TRIM32 protein, human; D044767:Ubiquitin-Protein Ligases; D024701:Myosin Type V; D018995:Myosin Heavy Chains; D009218:Myosins