Membrane Binding of the N-Terminal Ubiquitin-Like Domain of kindlin-2 Is Crucial for Its Regulation of Integrin Activation.Perera, H.D., Ma, Y.Q., Yang, J., Hirbawi, J., Plow, E.F., Qin, J.
(2011) Structure 19: 1664-1671
- PubMed: 22078565
- DOI: https://doi.org/10.1016/j.str.2011.08.012
- Primary Citation of Related Structures:
- PubMed Abstract:
Kindlin-2 belongs to an emerging class of regulators for heterodimeric (α/β) integrin adhesion receptors. By binding to integrin β cytoplasmic tail via its C-terminal FERM-like domain, kindlin-2 promotes integrin activation. Intriguingly, this activation process depends on the N terminus of kindlin-2 (K2-N) that precedes the FERM domain. The molecular function of K2-N is unclear. We present the solution structure of K2-N, which displays a ubiquitin fold similar to that observed in kindlin-1. Using chemical shift mapping and mutagenesis, we found that K2-N contains a conserved positively charged surface that binds to membrane enriched with negatively charged phosphatidylinositol-(4,5)-bisphosphate. We show that while wild-type kindlin-2 is capable of promoting integrin activation, such ability is significantly reduced for its membrane-binding defective mutant. These data suggest a membrane-binding function of the ubiquitin-like domain of kindlin-2, which is likely common for all kindlins to promote their localization to the plasma membrane and control integrin activation.
Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.