Identification of a novel Ca(2+)-regulated protein that is associated with the marginal band and centrosomes of chicken erythrocytes

摘要: We have identified a novel Ca(2+)-regulated protein, p23, that is expressed specifically in avian erythrocyte and thrombocyte lineages. Sequence analysis of this 23 kDa protein reveals it bears no homology to any known sequence. In mature definitive erythrocytes p23 exists equilibrium between soluble cytoskeletal bound pool. The fraction associated with the marginal band microtubules, centrosomes nuclear membrane under conditions low free [Ca2+]. An increase [Ca2+] 10(-6) M sufficient induce dissociation > 95% from its target binding sites, yet has little effect on calmodulin-mediated MB depolymerization. Analysis expression localization during erythropoiesis together results heterologous tissue cultured cells demonstrated does not behave as bone fide microtubule-associated protein. addition, developmental revealed although early erythropoeisis, association MB, centrosome occurs only final stages differentiation. This correlates marked stabilization accumulation at time being markedly downregulated. hypothesize mechanism may be induced part by decrease intracellular terminal erythropoiesis.