Elsevier, Journal of Biological Chemistry, 30(283), p. 21113-21119, 2008
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α-Parvin is an essential component of focal adhesions (FAs), which are large multiprotein complexes that link the plasma membrane and actin cytoskeleton. α-Parvin contains two calponin homology (CH) domains and its C-terminal CH2 domain binds multiple targets including paxillin LD motifs for regulating the FA network and signaling. Here we describe the solution structure of α-parvin CH2 bound to paxillin LD1. We show that although CH2 contains the canonical CH-fold, a previously defined N-terminal linker forms an α-helix that packs unexpectedly with the C-terminal helix of CH2, resulting in a novel variant of the CH domain. Importantly, such packing generates a hydrophobic surface that recognizes the Leu-rich face of paxillin-LD1, and the binding pattern differs drastically from the classical paxillin-LD binding to four-helix bundle proteins such as focal adhesion kinase. These results define a novel modular recognition mode and reveal how α-parvin associates with paxillin to mediate the FA assembly and signaling.