Split motifs

Many more motifs may be lurking in proteins than previously expected. Randen Patterson (Pennsylvania State University, State College, PA), Damian van Rossum, Solomon Snyder (Johns Hopkins University, Baltimore, MD), and colleagues report that functional protein–lipid interaction motifs can be formed when partial motifs from two proteins unite.

The group's initial example of a split domain comes in the context of a Ca²⁺ entry system. In this system, neurotransmitters bind receptors that trigger production of inositol 1,4,5-trisphosphate (IP3), which in turn prompts release of intracellular Ca²⁺ stores and entry of extracellular Ca²⁺ through TRPC3 channels. Snyder and colleagues previously established that phospholipase Cγ1 (PLC-γ1) was needed for this latter TRPC3 action, independent of PLC-γ1's enzymatic activity in generating IP3.

They now report that the binding of TRPC3 and PLC-γ1...