BERP, a novel ring finger protein, binds to alpha-actinin-4

me recently identified BERP as a novel RING finger protein belonging to the RBCC protein family. it contains an N-terminal RING finger, followed by a B-box zinc finger and a coiled-coil domain. BERP interacts with the tail do main of the class V myosins through a beta-propeller structure in the BERP C-terminal. To identify other proteins interacting with BERP, the S-east tw o-hybrid strategy was employed, using the RBCC domain as bait. Screening of a rat brain cDNA library identified alpha-actinin-4 as a specific binding partner for the N-terminus of BERP. This actinin isoform could be immunopre cipitated together with BERP from HEK 293 cells transfected with expression constructs for BERP and alpha-actinin-4. These proteins could also be colo calized immunohistochemically in the cytoplasm of differentiated PC12 cells . We suggest that BERP may anchor class V myosins to particular cell domain s Via its interaction with alpha-actinin-4. (C) 2000 Academic Press.