Phosphorylation of Annexin A1 by TRPM7 Kinase: A Switch Regulating the Induction of an α-Helix

TRPM7 is an unusual bifunctional protein consisting of an α-kinase domain fused to a TRP ion channel. Previously, we have identified annexin A1 as a substrate for TRPM7 kinase and found that TRPM7 phosphorylates annexin A1 at Ser5 within the N-terminal α-helix. Annexin A1 is a Ca2+-dependent membrane binding protein, which has been implicated in membrane trafficking and reorganization. The N-terminal tail of annexin A1 can interact with either...