Barbed end-capping protein regulates polarity of actin filaments from the human erythrocyte membrane.
The directional polymerization of G actin on single-layered erythrocyte membranes has been examined in the presence or absence of a barbed end-capping protein isolated from sea urchin eggs. When in the absence of the capping protein the single-layered erythrocyte membranes were incubated with 2 microM of G actin, exceeding the critical concentrations, about half of polymerized actin filaments became orientated with arrowheads of heavy meromyosin pointing toward the membrane at 2 microM of G actin. In contrast, in the presence of the capping protein, nearly 90% of the polymerized filaments were directed with arrowheads of HMM pointing away from the membranes. Furthermore, only preincubation of the erythrocyte membranes with the capping protein is effective to a similar extent in regulating the polarity of actin filaments from the membranes. The results obtained are discussed particular as regards to the physiological roles of the barbed end-capping protein in situ.
D000199:Actins / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure*; D004910:Erythrocyte Membrane / Q000378:metabolism / Q000648:ultrastructure*; D005260:Female; D018260:Gelsolin; D006801:Humans; D046911:Macromolecular Substances; D008840:Microfilament Proteins / Q000378:metabolism*; D010063:Ovum; D012617:Sea Urchins; D013049:Spectrin / Q000378:metabolism
D000199:Actins; D002352:Carrier Proteins; D018260:Gelsolin; D046911:Macromolecular Substances; D008840:Microfilament Proteins; C016953:brevin; D013049:Spectrin