CRP1, a LIM Domain Protein Implicated in Muscle Differentiation, Interacts with α-Actinin

摘要: Members of the cysteine-rich protein (CRP) family are LIM domain proteins that have been implicated in muscle differentiation. One strategy for defining mechanism by which CRPs potentiate myogenesis is to characterize repertoire CRP binding partners. In order identify interact with CRP1, a prominent fibroblasts and smooth cells, we subjected an avian extract affinity chromatography on CRP1 column. A 100-kD bound column could be eluted high salt buffer; Western immunoblot analysis confirmed α-actinin. We shown CRP1–α-actinin interaction direct, specific, saturable both solution solid-phase assays. The K d 1.8 ± 0.3 μM. results vitro studies supported double-label indirect immunofluorescence experiments demonstrate colocalization α-actinin along actin stress fibers CEF cells. Moreover, coimmunoprecipitates from detergent By mapping studies, determined associates 27-kD actin–binding reciprocal showed interacts CRP1-LIM1, deletion fragment contains NH2-terminal 107 amino acids (aa) CRP1. To determine whether would localize cytoskeleton living expression constructs encoding epitope-tagged full-length CRP1-LIM1(aa 1-107), or CRP1-LIM2 (aa 108-192) were microinjected into immunofluorescence, CRP1-LIM1 whereas fails associate cytoskeleton. Collectively these data part α-actinin–binding site sufficient association may critical its role