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.
Mesh Terms:
Adaptor Proteins, Signal Transducing, Amino Acid Sequence, Ankyrin Repeat, Binding Sites, Calorimetry, Cell Movement, DNA-Binding Proteins, Fluorescent Antibody Technique, Focal Adhesions, Humans, Immunoprecipitation, LIM Domain Proteins, Magnetic Resonance Spectroscopy, Membrane Proteins, Models, Molecular, Molecular Sequence Data, Protein Binding, Protein Conformation, Protein Structure, Tertiary, Protein-Serine-Threonine Kinases, Sequence Homology, Amino Acid, Transfection, Zinc Fingers
Adaptor Proteins, Signal Transducing, Amino Acid Sequence, Ankyrin Repeat, Binding Sites, Calorimetry, Cell Movement, DNA-Binding Proteins, Fluorescent Antibody Technique, Focal Adhesions, Humans, Immunoprecipitation, LIM Domain Proteins, Magnetic Resonance Spectroscopy, Membrane Proteins, Models, Molecular, Molecular Sequence Data, Protein Binding, Protein Conformation, Protein Structure, Tertiary, Protein-Serine-Threonine Kinases, Sequence Homology, Amino Acid, Transfection, Zinc Fingers
J. Biol. Chem.
Date: Feb. 27, 2009
PubMed ID: 19117955
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