The PIP2 binding mode of the C2 domains of rabphilin-3A

Pierre Montaville, Nicolas Coudevylle, Anand Radhakrishnan, Andrei Leonov, Markus Zweckstetter, Stefan Becker*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

Phosphatidylinositol-4,5-bisphosphate (PIP2) is a key player in the neurotransmitter release process. Rabphilin-3A is a neuronal C2 domain tandem containing protein that is involved in this process. Both its C2 domains (C2A and C2B) are able to bind PIP2. The investigation of the interactions of the two C2 domains with the PIP2 headgroup IP3 (inositol-1,4,5-trisphosphate) by NMR showed that a well-defined binding site can be described on the concave surface of each domain. The binding modes of the two domains are different. The binding of IP3 to the C2A domain is strongly enhanced by Ca2+ and is characterized by a KD of 55 μM in the presence of a saturating concentration of Ca2+ (5 mM). Reciprocally, the binding of IP3 increases the apparent Ca2+-binding affinity of the C2A domain in agreement with a Target-Activated Messenger Affinity (TAMA) mechanism. The C2B domain binds IP3 in a Ca2+-independent fashion with low affinity. These different PIP2 headgroup recognition modes suggest that PIP2 is a target of the C2A domain of rabphilin-3A while this phospholipid is an effector of the C2B domain. Published by Cold Spring Harbor Laboratory Press.

Original languageEnglish (US)
Pages (from-to)1025-1034
Number of pages10
JournalProtein Science
Volume17
Issue number6
DOIs
StatePublished - Jun 2008
Externally publishedYes

Keywords

  • C2 domain tandem
  • Calcium-binding protein
  • Haddock
  • IP3
  • NMR
  • Protein/ligand docking
  • Rabphilin-3A

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology

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