Open AccessTRPV4 mediates the calcium influx required for Flightless-non-muscle myosin interaction and collagen remodeling
Author(s) -
Pamma D. Arora,
Madeleine Di Gregorio,
Pei Jian He,
Christopher A. McCulloch
Publication year - 2017
Publication title -
journal of cell science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.384
H-Index - 278
eISSN - 1477-9137
pISSN - 0021-9533
DOI - 10.1242/jcs.201665
Subject(s) - trpv4 , microbiology and biotechnology , biology , integrin , förster resonance energy transfer , myosin , actin , collagen receptor , receptor , extracellular matrix , biophysics , transient receptor potential channel , biochemistry , fluorescence , physics , quantum mechanics
Collagen remodeling by phagocytosis requires cell extension formation, which in turn involves interaction of the actin binding protein Flightless I (FliI) with non-muscle myosin IIA (NMMIIA) at cell-matrix adhesion sites. As Ca2+ plays a central role in controlling actomyosin-dependent functions, we examined how Ca2+ controls the generation of cell extensions and collagen remodeling. Ratio fluorimetry demonstrated localized Ca2+ influx at extensions of fibroblasts. Western Blotting and qPCR showed high expression levels of the Ca2+-permeable, Transient Receptor Potential Vanilloid-4 (TRPV4) channel, which co-immunoprecipitated with β1 integrin and localized to adhesions. Blocking antibody to α2β1 integrin, the TRPV4-specific antagonist AB159908, or reduction of TRPV4 expression with siRNA, all blocked Ca2+ influx. These treatments also inhibited interaction of FliI with NMMIIA, reduced the number and length of cell extensions and blocked collagen remodeling. Pull-down assays showed that Ca2+ depletion inhibited interaction of purified FliI with NMMIIA filaments. Fluorescence resonance energy transfer experiments showed FliI-NMMIIA interactions require Ca2+ influx. We conclude that Ca2+ influx through TRPV4 channels regulates FliI-NMMIIA interactions, which in turn enable generation of the cell extensions essential for collagen remodeling.