Transient receptor potential (TRP) channels are polymodally regulated ion channels. TRPV4 (vanilloid 4) is sensitized by PIP 2 and desensitized by Syndapin3/PACSIN3, which bind to the structurally uncharacterized TRPV4 N terminus. We determined the nuclear magnetic resonance structure of the Syndapin3/PACSIN3 SH3 domain in complex with the TRPV4 N-terminal proline-rich region (PRR), which binds as a class I polyproline II (PPII) helix ...
Transient receptor potential (TRP) channels are polymodally regulated ion channels. TRPV4 (vanilloid 4) is sensitized by PIP 2 and desensitized by Syndapin3/PACSIN3, which bind to the structurally uncharacterized TRPV4 N terminus. We determined the nuclear magnetic resonance structure of the Syndapin3/PACSIN3 SH3 domain in complex with the TRPV4 N-terminal proline-rich region (PRR), which binds as a class I polyproline II (PPII) helix. This PPII conformation is broken by a conserved proline in a cis conformation. Beyond the PPII, we find that the proximal TRPV4 N terminus is unstructured, a feature conserved across species thus explaining the difficulties in resolving it in previous structural studies. Syndapin/PACSIN SH3 domain binding leads to rigidification of both the PRR and the adjacent PIP 2 binding site. We determined the affinities of the TRPV4 N terminus for PACSIN1, 2, and 3 SH3 domains and PIP 2 and deduce a hierarchical interaction network where Syndapin/PACSIN binding influences the PIP 2 binding site but not vice versa.
Organizational Affiliation:
Institute for Pharmacy and Biochemistry, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany; Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-Universität, 60438 Frankfurt am Main, Germany. Electronic address: u.hellmich@uni-mainz.de.
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