7CQH

Complex of TRP_CBS2 and Calmodulin_Clobe

Summary for 7CQH

• Entry DOI: 10.2210/pdb7cqh/pdb
• Descriptor: AT15141p, Transient receptor potential protein, CALCIUM ION (3 entities in total)
• Functional Keywords: calmodulin, trp channel, signaling protein
• Biological source: Drosophila melanogaster (Fruit fly); More
• Total number of polymer chains: 2
• Total formula weight: 13311.78

Authors

Shen, Z.S. (deposition date: 2020-08-10, release date: 2021-06-23, Last modification date: 2023-11-29)

Primary citation

Chen, W.,Shen, Z.,Asteriti, S.,Chen, Z.,Ye, F.,Sun, Z.,Wan, J.,Montell, C.,Hardie, R.C.,Liu, W.,Zhang, M.
Calmodulin binds to Drosophila TRP with an unexpected mode.
Structure, 29:330-344.e4, 2021

PubMed Abstract: Drosophila TRP is a calcium-permeable cation channel essential for fly visual signal transduction. During phototransduction, Ca mediates both positive and negative feedback regulation on TRP channel activity, possibly via binding to calmodulin (CaM). However, the molecular mechanism underlying Ca modulated CaM/TRP interaction is poorly understood. Here, we discover an unexpected, Ca-dependent binding mode between CaM and TRP. The TRP tail contains two CaM binding sites (CBS1 and CBS2) separated by an ∼70-residue linker. CBS1 binds to the CaM N-lobe and CBS2 recognizes the CaM C-lobe. Structural studies reveal the lobe-specific binding of CaM to CBS1&2. Mutations introduced in both CBS1 and CBS2 eliminated CaM binding in full-length TRP, but surprisingly had no effect on the response to light under physiological conditions, suggesting alternative mechanisms governing Ca-mediated feedback on the channel activity. Finally, we discover that TRPC4, the closest mammalian paralog of Drosophila TRP, adopts a similar CaM binding mode.

PubMed: 33326749
DOI: 10.1016/j.str.2020.11.016

Experimental method

X-RAY DIFFRACTION (2.15 Å)