title: Phosphatidylinositol 4,5-bisphosphate triggers activation of focal adhesion kinase by inducing clustering and conformational changes.
abstract: Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase (NRTK) with key roles in integrating growth and cell matrix adhesion signals, and FAK is a major driver of invasion and metastasis in cancer. Cell adhesion via integrin receptors is well known to trigger FAK signaling, and many of the players involved are known; however, mechanistically, FAK activation is not understood. Here, using a multidisciplinary approach, including biochemical, biophysical, structural, computational, and cell biology approaches, we provide a detailed view of a multistep activation mechanism of FAK initiated by phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2]. Interestingly, the mechanism differs from canonical NRTK activation and is tailored to the dual catalytic and scaffolding function of FAK. We find PI(4,5)P2 induces clustering of FAK on the lipid bilayer by binding a basic region in the regulatory 4.1, ezrin, radixin, moesin homology (FERM) domain. In these clusters, PI(4,5)P2 induces a partially open FAK conformation where the autophosphorylation site is exposed, facilitating efficient autophosphorylation and subsequent Src recruitment. However, PI(4,5)P2 does not release autoinhibitory interactions; rather, Src phosphorylation of the activation loop in FAK results in release of the FERM/kinase tether and full catalytic activation. We propose that PI(4,5)P2 and its generation in focal adhesions by the enzyme phosphatidylinositol 4-phosphate 5-kinase type Iγ are important in linking integrin signaling to FAK activation.
authors: Structural Biology and Biocomputing Program and.
authors: Guillermina M
authors: GM
authors: Goñi
authors: BBVA Foundation Cancer Cell Biology Program, Spanish National Cancer Research Centre, 28029 Madrid, Spain;
authors: Carolina
authors: C
authors: Epifano
authors: Structural Biology and Biocomputing Program and.
authors: Jasminka
authors: J
authors: Boskovic
authors: Structural Biology and Biocomputing Program and.
authors: Marta
authors: M
authors: Camacho-Artacho
authors: Heidelberg Institute for Theoretical Studies, 69118 Heidelberg, Germany;
authors: Jing
authors: J
authors: Zhou
authors: Heidelberg Institute for Theoretical Studies, 69118 Heidelberg, Germany;
authors: Agnieszka
authors: A
authors: Bronowska
authors: Immunology and Oncology Department, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain;
authors: M Teresa
authors: MT
authors: Martín
authors: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115;Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115; and.
authors: Michael J
authors: MJ
authors: Eck
authors: Immunology and Oncology Department, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain;
authors: Leonor
authors: L
authors: Kremer
authors: Heidelberg Institute for Theoretical Studies, 69118 Heidelberg, Germany;
authors: Frauke
authors: F
authors: Gräter
authors: Institute of Structural and Molecular Biology andDepartment of Chemistry, University College London, London WC1H 0AJ, United Kingdom.
authors: Francesco Luigi
authors: FL
authors: Gervasio
authors: BBVA Foundation Cancer Cell Biology Program, Spanish National Cancer Research Centre, 28029 Madrid, Spain;
authors: Mirna
authors: M
authors: Perez-Moreno
authors: Structural Biology and Biocomputing Program and dlietha@cnio.es.
authors: Daniel
authors: D
authors: Lietha
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000494:Allosteric Regulation / Q000187:drug effects; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism; D055162:Biocatalysis / Q000187:drug effects; D002448:Cell Adhesion / Q000187:drug effects; D016000:Cluster Analysis; D004789:Enzyme Activation / Q000187:drug effects; D031541:Fluorescence Resonance Energy Transfer; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D015398:Signal Transduction / Q000187:drug effects; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D000596:Amino Acids; D050505:Mutant Proteins; D019269:Phosphatidylinositol 4,5-Diphosphate; D000255:Adenosine Triphosphate; D017853:Phosphotransferases (Alcohol Group Acceptor); C020077:1-phosphatidylinositol-4-phosphate 5-kinase; D051416:Focal Adhesion Protein-Tyrosine Kinases; D019061:src-Family Kinases
keywords: cell signaling; phosphoinositides