PDBsum entry 2j0l

Transferase

PDB id: 2j0l

Contents

Protein chain

276 a.a.

Ligands

SO4

ANP

Metals

_MG

Waters ×97

References listed in PDB file

Key reference

Title

Structural basis for the autoinhibition of focal adhesion kinase.

Authors

D.Lietha, X.Cai, D.F.Ceccarelli, Y.Li, M.D.Schaller, M.J.Eck.

Ref.

Cell, 2007, 129, 1177-1187. [DOI no: 10.1016/j.cell.2007.05.041]

PubMed id

17574028

Abstract

Appropriate tyrosine kinase signaling depends on coordinated sequential coupling of protein-protein interactions with catalytic activation. Focal adhesion kinase (FAK) integrates signals from integrin and growth factor receptors to regulate cellular responses including cell adhesion, migration, and survival. Here, we describe crystal structures representing both autoinhibited and active states of FAK. The inactive structure reveals a mechanism of inhibition in which the N-terminal FERM domain directly binds the kinase domain, blocking access to the catalytic cleft and protecting the FAK activation loop from Src phosphorylation. Additionally, the FERM domain sequesters the Tyr397 autophosphorylation and Src recruitment site, which lies in the linker connecting the FERM and kinase domains. The active phosphorylated FAK kinase adopts a conformation that is immune to FERM inhibition. Our biochemical and structural analysis shows how the architecture of autoinhibited FAK orchestrates an activation sequence of FERM domain displacement, linker autophosphorylation, Src recruitment, and full catalytic activation.

Figure 1.
Figure 1. Structure of Autoinhibited FAK
(A) Domain structure of FAK. Key tyrosine phosphorylation sites are indicated.
(B) Overall structure of autoinhibited FAK including the FERM, linker, and kinase regions. In the autoinhibited state, the FERM domain (blue ribbon representation) binds the kinase domain (red), primarily through an interaction between the FERM F2 lobe and the kinase C-lobe. A section of the linker that contains the autophosphorylation site Tyr397 (yellow) is located between the FERM F1 lobe and the kinase N-lobe. The FERM domain also blocks access to the active-site cleft and to the kinase activation loop (A-loop, green). Disordered segments are indicated as dashed lines. The staurosporine analog AFN941 is bound to the active site of the kinase and is shown in stick representation.
(C) Sequence alignment of the FERM, linker, and kinase regions of avian FAK (cFAK1), human FAK (hFAK1), and human Pyk2 (hPyk2). cFAK1 shares 94% sequence identity with hFAK1, and hFAK1 shares 43% with hPyk2. Secondary structure elements are indicated, and the sequence is shaded to correspond to the colors in (B). Residues involved in the FERM F2 lobe/kinase C-lobe interaction are indicated by an asterisk, and regulatory tyrosines are colored magenta.

Figure 2.
Figure 2. Structure of the Active Kinase Domain of FAK
(A) The structure of the FAK kinase domain phosphorylated by Src is shown in ribbon representation (green) with the activation loop in blue. The side chains of phosphotyrosines 576 and 577 and AMP-PNP, which is bound to the active site, are shown in stick representation. A Mg^2+ ion at the active site is shown as a yellow sphere.
(B) Close-up view of the activation loop with the side chains of pY576, pY577, R569, and R545 and the main chains of A579 and S580 shown in stick representation. A network of hydrogen bonds (orange dashed lines) involving the phosphate group of pY577 stabilizes the conformation of the activation loop.
(C) Superposition of active and inactive FAK kinases. The autoinhibited structure is shown with the FERM domain as a surface representation (light blue), and the linker and kinase domains are shown in a ribbon representation colored yellow and red, respectively. The structure of the active kinase domain (green ribbon and blue activation loop) is superimposed based on the kinase C-lobes. The side chain of pY576 and the main chain carbonyl of A579 in the active kinase (both residues are shown in space filling representations) clash with the FERM domain in the autoinhibited structure.

The above figures are reprinted by permission from Cell Press: Cell (2007, 129, 1177-1187) copyright 2007.