Testin, a novel binding partner of the calcium-sensing receptor, enhances receptor-mediated Rho-kinase signalling

► A yeast two-hybrid screen revealed testin bound to the calcium-sensing receptor. ► The second zinc finger of LIM domain 1 of testin is critical for interaction. ► Testin bound to a region of the receptor tail important for cell signalling. ► Testin and receptor interaction was confirmed in mammalian (HEK293) cells. ► Overexpression of testin enhanced receptor-mediated Rho signalling in HEK293 cells.