The presence of RGS8 in the microtubule fraction of the cerebellum

Abstract

To search proteins contributing cellular regulation of distribution of regulators of G-protein signaling (RGS8), we carried out a two-hybrid screening for RGS8-interacting proteins. We isolated four overlapping clones of KIF1A, a member of kinesin superfamily proteins. We found that RGS8 binds to the middle part (641-771aa) of KIF1A using the N-terminal sequence 16-35aa of RGS8. KIF1A of the cerebellum could be precipitated with recombinant RGS8 protein-bound beads. We further observed that RGS8 is present in microtubules prepared from the cerebellum by using Western blotting and immunoelectron microscopy. RGS2 can also bind to KIF1A. These observations showed that B/R4 members of RGS proteins are able to bind to microtubules through KIF1A and might be transported on microtubules in neurons.