Structural basis of focal adhesion localization of LIM-only adaptor PINCH by integrin-linked kinase.
The LIM-only adaptor PINCH (the particularly interesting cysteine- and histidine-rich protein) plays a pivotal role in the assembly of focal adhesions (FAs), supramolecular complexes that transmit mechanical and biochemical information between extracellular matrix and actin cytoskeleton, regulating diverse cell adhesive processes such as cell migration, cell spreading, and survival. A key step for the PINCH function is its localization to FAs, which depends critically on the tight binding of PINCH to integrin-linked kinase (ILK). Here we report the solution NMR structure of the core ILK.PINCH complex (28 kDa, K(D) approximately 68 nm) involving the N-terminal ankyrin repeat domain (ARD) of ILK and the first LIM domain (LIM1) of PINCH. We show that the ILK ARD exhibits five sequentially stacked ankyrin repeat units, which provide a large concave surface to grip the two contiguous zinc fingers of the PINCH LIM1. The highly electrostatic interface is evolutionally conserved but differs drastically from those of known ARD and LIM bound to other types of protein domains. Consistently mutation of a hot spot in LIM1, which is not conserved in other LIM domains, disrupted the PINCH binding to ILK and abolished the PINCH targeting to FAs. These data provide atomic insight into a novel modular recognition and demonstrate how PINCH is specifically recruited by ILK to mediate the FA assembly and cell-extracellular matrix communication.
Yang
Yanwu
Y
Department of Molecular Cardiology, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195, USA.
Wang
Xiaoxia
X
Hawkins
Cheryl A
CA
Chen
Kan
K
Vaynberg
Julia
J
Mao
Xian
X
Tu
Yizeng
Y
Zuo
Xiaobing
X
Wang
Jinbu
J
Wang
Yun-Xing
YX
Wu
Chuanyue
C
Tjandra
Nico
N
Qin
Jun
J
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D017089:Ankyrin Repeat; D001665:Binding Sites; D002151:Calorimetry; D002465:Cell Movement; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D022001:Focal Adhesions / Q000502:physiology*; D006801:Humans; D047468:Immunoprecipitation; D060588:LIM Domain Proteins; D009682:Magnetic Resonance Spectroscopy; D008565:Membrane Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D016335:Zinc Fingers; D000099200:Scaffold Protein ILK
D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; D060588:LIM Domain Proteins; D008565:Membrane Proteins; D017346:Protein Serine-Threonine Kinases; D000099200:Scaffold Protein ILK; C088088:LIMS1 protein, human