AFAP-110 regulates signals that affect F-actin

描述（由申请人提供）：AFAP-110是Src和PKCalpha的结合伙伴，作为肌动蛋白丝交联蛋白和证监会激活蛋白影响肌动蛋白丝完整性的变化。我们的数据支持这样的假设，即AFAP-110传递来自PKCalpha的信号，促进(i)肌动蛋白丝交联和（ii）证监会的激活。这两种功能与细胞运动有关，因为细胞前缘需要肌动蛋白丝交联来为板足的延伸提供突出的力，而证监会激活会导致肌动蛋白丝在细胞体上完整性的丧失，并刺激下游信号，促进运动和侵袭。AFAP-110交联肌动蛋白丝和激活证监会的内在能力在PKCalpha信号的响应中被揭示。在体内和体外，AFAP-110是PKCalpha的结合伙伴和底物。与PKCa的相互作用会影响AFAP-110的构象变化，从而促进其交联肌动蛋白丝的能力。PKCalpha激活也通过SH3结合指导AFAP-110移动到证监会并激活证监会。活化形式的AFAP-110可以独立激活证监会，促进细胞运动和侵袭。显性阴性的AFAP-110将阻断pkcalpha导向的证监会激活和肌动蛋白丝完整性的改变。该项目将确定AFAP-110传递PKCalpha信号的机制，这些信号调节(i)肌动蛋白丝交联，（ii）证监会激活和（iii）细胞运动和侵袭。这项工作的意义在于(a)证监会激活与人类肿瘤侵袭性表型的获得相关，(b) AFAP-110可以激活证监会并影响细胞运动和侵袭性，(c) PKCa、证监会和AFAP-110在侵袭性乳腺癌组织和细胞系中上调。因此，在PKCalpha和证监会被激活的侵袭性癌症中，AFAP-110可能是一种新的生物标志物或干预靶点。

DESCRIPTION (provided by applicant): AFAP-110 is a binding partner for Src and PKCalpha and affects changes in actin filament integrity as an actin filament cross linking protein and as a cSrc activating protein. Our data support the hypothesis that AFAP-110 relays signals from PKCalpha that promote (i) actin filament cross linking and (ii) activation of cSrc. These two functions are relevant to cell motility as actin filament cross linking is required at the leading edge of a cell to provide protrusive force for extension of lamellipodia, while cSrc activation directs a loss of actin filament integrity across the cell body and stimulates downstream signals that promote motility and invasion. The intrinsic ability of AFAP-110 to cross link actin filaments and activate cSrc is revealed in response to PKCalpha signaling. AFAP-110 is a binding partner and substrate for PKCalpha, in vivo and in vitro. Interactions with PKCa affect a conformational change upon AFAP-110 that promotes its ability to cross link actin filaments. PKCalpha activation also directs AFAP-110 to move to and activate cSrc through SH3 binding. Activated forms of AFAP-110 can independently activate cSrc and promote cell motility and invasion. Dominant-negative AFAP-110 will block PKCalpha-directed cSrc activation and changes in actin filament integrity. This project will determine the mechanism by which AFAP-110 relays signals from PKCalpha that regulate (i) actin filament cross linking, (ii) cSrc activation and (iii) cell motility and invasion. The significance of this work is that (a) cSrc activation correlates with acquisition of the invasive phenotype in human tumors, (b) AFAP-110 can activate cSrc and affect both cellular motility and invasion and (c) PKCa, cSrc and AFAP-110 are upregulated in breast cancer tissues and cell lines that are invasive. Thus, AFAP-110 may be a novel biomarker or target for intervention in invasive cancers where PKCalpha and cSrc are activated.