Calmodulin binds to Drosophila TRP with an unexpected mode

Weidi Chen; Zeyu Shen; Sabrina Asteriti; Zijing Chen; Fei Ye; Ziling Sun; Jun Wan; Craig Montell; Roger C Hardie; Wei Liu; Mingjie Zhang

doi:10.1016/j.str.2020.11.016

Calmodulin binds to Drosophila TRP with an unexpected mode

Structure. 2021 Apr 1;29(4):330-344.e4. doi: 10.1016/j.str.2020.11.016. Epub 2020 Dec 15.

Authors

Weidi Chen¹, Zeyu Shen², Sabrina Asteriti³, Zijing Chen⁴, Fei Ye², Ziling Sun⁵, Jun Wan⁶, Craig Montell⁴, Roger C Hardie⁷, Wei Liu⁸, Mingjie Zhang⁹

Affiliations

¹ Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China; Greater Bay Biomedical Innocenter, Shenzhen Bay Laboratory, Shenzhen 518055, China.
² Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
³ Department of Physiology, Development and Neuroscience, Cambridge University, Downing St, Cambridge CB2 3EG, UK; Department of Neurosciences, Biomedicine and Movement Science, University of Verona, Verona, Italy.
⁴ Department of Molecular, Cellular and Developmental Biology, and the Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, United States.
⁵ Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China.
⁶ Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China; Greater Bay Biomedical Innocenter, Shenzhen Bay Laboratory, Shenzhen 518055, China; Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
⁷ Department of Physiology, Development and Neuroscience, Cambridge University, Downing St, Cambridge CB2 3EG, UK.
⁸ Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China. Electronic address: liuwei@sphmc.org.
⁹ Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China; Greater Bay Biomedical Innocenter, Shenzhen Bay Laboratory, Shenzhen 518055, China; Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China. Electronic address: mzhang@ust.hk.

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

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.

Keywords: Ca(2+)-dependent target binding; Drosophila TRP; TRPC4; calmodulin; visual signal transduction.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Animals
Binding Sites
Calcium / metabolism
Calmodulin / chemistry*
Calmodulin / metabolism
Drosophila Proteins / chemistry*
Drosophila Proteins / genetics
Drosophila Proteins / metabolism
Drosophila melanogaster
HEK293 Cells
Humans
Mice
Mutation
Protein Binding
TRPC Cation Channels / chemistry
TRPC Cation Channels / metabolism
Transient Receptor Potential Channels / chemistry*
Transient Receptor Potential Channels / genetics
Transient Receptor Potential Channels / metabolism

Substances

Calmodulin
Drosophila Proteins
TRPC Cation Channels
TRPC4 ion channel
Transient Receptor Potential Channels
trp protein, Drosophila
Calcium

Grants and funding

BB/M007006/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom