The long term goal of the proposed studies is to understand the signal transduction mechanisms in the regulation of cell migration. Previous funding period focused on the role of focal adhesion kinase (FAK) and its downstream target Grb7 and a putative novel FAK inhibitor FIP200 in the regulation of cell migration. We identified and characterized Grb7 interaction with phosphoinositides through its PH domain and a role for Grb7 in mediating EphB1 stimulation of cell migration, showed the critical importance of focal contacts localization of the FAK signaling complexes, and characterized FIP200 inhibition of FAK activity and cell migration. We also found an interaction between FAK and N-WASP and showed that FAK phosphorylation of N-WASP regulates N-WASP subcellular localization and promotion of cell migration. In addition, we found an interaction between integrin p1 and 14-3-3p and studied the role of 14-3-3p in the regulation of cell spreading and migration, and an intra-molecular interaction between the N-terminal FERM-like domain and the kinase domain of FAK that regulate FAK activation in an auto-inhibitory mechanism. In preliminary studies, we identified an interaction between FAK and endophilin A2 and showed that endophilin A2 association with FAK and phosphorylation by FAK/Src complex regulated its interaction with dynamin and affected invasion of Src transformed cells. We are also in the process of creating mammary epithelial-specific FAK conditional knockout mice to study the role of FAK and its interaction with endophilin A2 in breast cancer metastasis in vivo. Lastly, to facilitate studies of directional cell migration on ECMgradients which better mimic in vivo conditions, we fabricated microfluidics devices to generate defined and quantitative FN gradients and showed directional cell migration on the gradients with novel properties. In this proposal, we will 1) determine the mechanism and role of FAK interaction with endophilin A2 in the regulation of cell migration and invasion, 2) investigate the potential role of FAK and its interaction with endophilin A2 in cancer metastasis in vivo, and 3) analyze the responses and roles of FAK and other signaling molecules in directional cell migration on defined FN gradients. These studies will enhance our understanding of the molecular mechanisms of signal transduction in cell migration and invasion which are critical factors in biological processes such as embryonic development, wound healing and cancer.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Special Emphasis Panel (ZRG1-ICI-G (01))
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Flicker, Paula F
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University of Michigan Ann Arbor
Internal Medicine/Medicine
Schools of Medicine
Ann Arbor
United States
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Peng, Xu; Guan, Jun-Lin (2011) Focal adhesion kinase: from in vitro studies to functional analyses in vivo. Curr Protein Pept Sci 12:52-67
Luo, Ming; Guan, Jun-Lin (2010) Focal adhesion kinase: a prominent determinant in breast cancer initiation, progression and metastasis. Cancer Lett 289:127-39
Guan, Jun-Lin (2010) Integrin signaling through FAK in the regulation of mammary stem cells and breast cancer. IUBMB Life 62:268-76
Yoo, Y; Ho, H J; Wang, C et al. (2010) Tyrosine phosphorylation of cofilin at Y68 by v-Src leads to its degradation through ubiquitin-proteasome pathway. Oncogene 29:263-72
Luo, Ming; Fan, Huaping; Nagy, Tamas et al. (2009) Mammary epithelial-specific ablation of the focal adhesion kinase suppresses mammary tumorigenesis by affecting mammary cancer stem/progenitor cells. Cancer Res 69:466-74
Zhao, Jihe; Guan, Jun-Lin (2009) Signal transduction by focal adhesion kinase in cancer. Cancer Metastasis Rev 28:35-49
Rhoads, Daniel S; Guan, Jun-Lin (2007) Analysis of directional cell migration on defined FN gradients: role of intracellular signaling molecules. Exp Cell Res 313:3859-67
Nagy, Tamas; Wei, Huijun; Shen, Tang-Long et al. (2007) Mammary epithelial-specific deletion of the focal adhesion kinase gene leads to severe lobulo-alveolar hypoplasia and secretory immaturity of the murine mammary gland. J Biol Chem 282:31766-76
Liang, Chun-Chi; Park, Ann Y; Guan, Jun-Lin (2007) In vitro scratch assay: a convenient and inexpensive method for analysis of cell migration in vitro. Nat Protoc 2:329-33
Cohen, Lee Ann; Guan, Jun-Lin (2005) Mechanisms of focal adhesion kinase regulation. Curr Cancer Drug Targets 5:629-43

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