Crystallization and preliminary X-ray crystallographic analysis of human RGS10 complexed with Galphai3.

G-protein-coupled receptors, which are major targets for drug discovery, play a major role in diverse physiological processes by relating changes in the extracellular environment to intracellular functions via activation of heterotrimeric G-proteins. However, G-protein activity is also modulated by a family of proteins called regulators of G-protein signalling (RGS), which are classified into six subfamilies. RGS10 belongs to the subgroup D/R12 and is known to act specifically on activated forms of three Galpha proteins (Galphai3, Galphaz and Galphao but not Galphas). It is abundantly expressed in brain and immune tissues and has been implicated in the pathophysiology of schizophrenia. The RGS domain of RGS10 was cloned, purified, complexed with human Galphai3 and crystallized. The crystals containing both RGS and Galphai3 belong to space group P4(3)2(1)2 (or P4(1)2(1)2), with unit-cell parameters a = 99.88, b = 99.88, c = 144.59 A, alpha = beta = gamma = 90 degrees . A full set of diffraction data were collected to 2.5 A resolution at 100 K using synchrotron radiation at Pohang beamline 4A.