In a recent issue of Nature, van Rossum et al. report binding of a "split" pleckstrin homology (PH) domain from phospholipase C-gamma(1) to the TRPC3 ion channel. Through sequence analyses and in vitro studies, they suggest a novel mode of protein-protein interaction in which two PH domain fragments in distinct proteins associate to form an "intermolecular" PH domain that binds inositol phospho...