PDBsum entry 7cqh

Signaling protein

PDB id: 7cqh

Contents

Protein chains

68 a.a.

24 a.a.

Metals

_CA ×2

PDB id:

7cqh

Name:

Signaling protein

Title:

Complex of trp_cbs2 and calmodulin_clobe

Structure:

At15141p. Chain: b. Synonym: cam_clobe. Engineered: yes. Transient receptor potential protein. Chain: a. Fragment: cbs2. Engineered: yes

Source:

Drosophila melanogaster. Fruit fly. Organism_taxid: 7227. Gene: cam-rb. Expressed in: escherichia coli. Expression_system_taxid: 562. Gene: trp, cg7875. Expression_system_taxid: 562

Resolution:

2.15Å R-factor: 0.216 R-free: 0.253

Authors:

Z.S.Shen

Key ref:

W.Chen et al. (2021). Calmodulin binds to Drosophila TRP with an unexpected mode. Structure, 29, 330. PubMed id: 33326749 DOI: 10.1016/j.str.2020.11.016

Date:

10-Aug-20 Release date: 23-Jun-21

Protein chain

P62152  (CALM_DROME) -  Calmodulin from Drosophila melanogaster

Seq: 149 a.a.

Struc: 68 a.a.

Protein chain

P19334  (TRP_DROME) -  Transient receptor potential protein from Drosophila melanogaster

Seq: 1275 a.a.

Struc: 24 a.a.

DOI no: 10.1016/j.str.2020.11.016

Structure 29:330 (2021)

PubMed id: 33326749

Calmodulin binds to Drosophila TRP with an unexpected mode.

W.Chen, Z.Shen, S.Asteriti, Z.Chen, F.Ye, Z.Sun, J.Wan, C.Montell, R.C.Hardie, W.Liu, M.Zhang.

ABSTRACT

Drosophila TRP is a calcium-permeable cation channel essential for fly visual signal transduction. During phototransduction, Ca²⁺ mediates both positive and negative feedback regulation on TRP channel activity, possibly via binding to calmodulin (CaM). However, the molecular mechanism underlying Ca²⁺ modulated CaM/TRP interaction is poorly understood. Here, we discover an unexpected, Ca²⁺-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 Ca²⁺-mediated feedback on the channel activity. Finally, we discover that TRPC4, the closest mammalian paralog of Drosophila TRP, adopts a similar CaM binding mode.