AFAP-110 regulates signals that affect F-actin

描述(申请人提供)：AFAP-110是Src和PKCalpha的结合伙伴，作为肌动蛋白细丝交联蛋白和CSRC激活蛋白影响肌动蛋白细丝完整性的变化。我们的数据支持这样的假设：AFAP-110传递来自PKCalpha的信号，促进(I)肌动蛋白细丝交联和(Ii)激活CSRC。这两个功能与细胞运动有关，因为肌动蛋白细丝在细胞的前沿需要交联，为片状脂膜的延伸提供突出力，而CSRC的激活引导整个细胞体肌动蛋白细丝完整性的丧失，并刺激促进运动和侵袭的下游信号。通过对PKCalpha信号的响应，揭示了AFAP-110具有使肌动蛋白细丝交联并激活CSRC的内在能力。AFAP-110在体内和体外都是PKCalpha的结合伙伴和底物。与PKCA的相互作用影响AFAP-110的构象变化，从而促进其交联肌动蛋白细丝的能力。PKCalpha的激活也引导AFAP-110通过SH3结合移动到CSRC并激活。激活形式的AFAP-110可以独立激活CSRC，促进细胞运动和侵袭。显性负性AFAP-110将阻断PKCalpha诱导的CSRC激活和肌动蛋白细丝完整性的变化。这个项目将确定AFAP-110传递来自PKCalpha的信号的机制，这些信号调节(I)肌动蛋白细丝交联，(Ii)CSRC激活和(Iii)细胞运动和侵袭。这项工作的意义在于：(A)CSRC的激活与肿瘤侵袭表型的获得有关，(B)AFAP-110可以激活CSRC，影响细胞的运动和侵袭，(C)PKCA、CSRC和AFAP-110在乳腺癌组织和侵袭性细胞系中上调。因此，AFAP-110可能是一种新的生物标志物或靶点，用于干预PKCalpha和CSRC激活的浸润性癌症。

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.