Actin is a major cytoskeletal protein involved in diverse cellular functions including cell motility, adhesion, and morphology. Six different actin isoforms have been identified in vertebrates. There are four α isoforms: skeletal, cardiac, and two smooth muscle (enteric and aortic) actins, along with two cytoplasmic actins (β and γ). Actin exists in two principal forms, globular, monomeric (G) actin, and filamentous polymeric (F) actin. The assembly and disassembly of actin filaments, and also their organization into functional networks, is regulated by a variety of actin-binding proteins (ABPs). Phosphorylation may also be important for regulating actin assembly and interaction with ABPs. In Dictyostelium, phosphorylation of Tyr-53 occurs in response to cell stress and this phosphorylation may alter actin polymerization. In B cells, SHP-1 tyrosine dephosphorylation of actin leads to actin filament depolymerization following BCR stimulation.

 

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ECM BIOSCIENCES的A431细胞裂解液A431细胞在细胞表面表达约106种表皮生长因子（EGF）受体。在用EGF刺激后，A431细胞的EGF受体磷酸化水平显着增加，随后激活了主要的细胞信号传导途径，例如PKB / Akt和MAP激酶途径。在EGF刺激后的不同时间点，这些细胞信号通路的下游，各种细胞骨架，细胞质和核蛋白被磷酸化。在含有10％胎牛血清的DMEM中生长的A431细胞的融合培养物在1％SDS，1.0 mM原钒酸钠，10 mM Tris（pH 7.4）缓冲液中裂解。在稀释至最终浓度和缓冲液之前，使用BCA方法（Pierce）确定蛋白质浓度。