Annexin VI-binding proteins in brain. Interaction of annexin VI with a membrane skeletal protein, calspectin (brain spectrin or fodrin).

摘要: Identification of annexin VI-binding proteins is essential to elucidate the physiological functions VI. Here, we developed methods identify an protein and characterized binding. Annexin VI bound about 14 species in whole homogenate rat forebrain, when examined with 125I-annexin using blots SDS-polyacrylamide gels. The binding was Ca(2+)-dependent specific for phosphatidylserine (PS) phosphatidic acid. A line evidence indicates that its target a protein-protein interaction. One M(r) 240,000 enriched cytoskeletal fraction identified as calspectin (brain spectrin or fodrin). When purified native state, Ca2+ affinity (KCa) 7.6 microM, (Kd) 68 nM. beta subunit calspectin, but not alpha subunit. site localized NH2-terminal domain subunit, which contains actin-binding exhibits striking homology regions dystrophin alpha-actinin. effect on interaction between F-actin by low shear viscometry, inhibited cross-linking activity Ca2+/PS-dependent manner. Cosedimentation assay showed dissociates from presence PS. These results suggest can dissociate redistribute Ca2+/phospholipid-dependent manner under plasma membrane may be involved regulation skeleton neuronal cells response Ca2+.