Beta-dystrobrevin interacts directly with kinesin heavy chain in brain.
Beta-dystrobrevin, a member of the dystrobrevin protein family, is a dystrophin-related and -associated protein restricted to non-muscle tissues and is highly expressed in kidney, liver and brain. Dystrobrevins are now thought to play an important role in intracellular signal transduction, in addition to providing a membrane scaffold in muscle, but the precise role of beta-dystrobrevin has not yet been determined. To study beta-dystrobrevin's function in brain, we used the yeast two-hybrid approach to look for interacting proteins. Four overlapping clones were identified that encoded Kif5A, a neuronal member of the Kif5 family of proteins that consists of the heavy chains of conventional kinesin. A direct interaction of beta-dystrobrevin with Kif5A was confirmed by in vitro and in vivo association assays. Co-immunoprecipitation with a monoclonal kinesin heavy chain antibody precipitated both alpha- and beta-dystrobrevin, indicating that this interaction is not restricted to the beta-dystrobrevin isoform. The site for Kif5A binding to beta-dystrobrevin was localized in a carboxyl-terminal region that seems to be important in heavy chain-mediated kinesin interactions and is highly homologous in all three Kif5 isoforms, Kif5A, Kif5B and Kif5C. Pull-down and immunofluorescence experiments also showed a direct interaction between beta-dystrobrevin and Kif5B. Our findings suggest a novel function for dystrobrevin as a motor protein receptor that might play a major role in the transport of components of the dystrophin-associated protein complex to specific sites in the cell.
Macioce
P
P
Laboratory of Cell Biology, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy. macioce@iss.it
Gambara
G
G
Bernassola
M
M
Gaddini
L
L
Torreri
P
P
Macchia
G
G
Ramoni
C
C
Ceccarini
M
M
Petrucci
T C
TC
D000818:Animals; D001921:Brain / Q000378:metabolism; D019556:COS Cells; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D049029:Dystrophin-Associated Proteins; D015723:Gene Library; D016547:Kinesins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008856:Microscopy, Fluorescence; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism; D017434:Protein Structure, Tertiary; D020798:Two-Hybrid System Techniques
D049029:Dystrophin-Associated Proteins; D008565:Membrane Proteins; D020033:Protein Isoforms; C098885:dystrobrevin; C475469:Kif5b protein, mouse; D016547:Kinesins