bioRxiv Science⌕ Search

bioRxiv · 10.1101/330993

TRPV4 interacts with mitochondrial proteins and acts as a mitochondrial structure-function regulator

Abstract

TRPV4 has been linked with the development of sensory defects, neuropathic pain, neurodegenerative disorders such as Charcot Marie Tooth disease and various muscular dystrophies. In all these cases mitochondrial abnormalities were tagged as cellular hallmarks and such abnormalities have been reported as key factor for the pathophysiological conditions. Mitochondria also have the unique ability to sense and regulate their own temperature. Here, we demonstrate that TRPV4, a thermosensitive ion channels, localizes to a subpopulation of mitochondria in various cell lines, in primary cells and also in sperm cells. Improper expression and/or function of TRPV4 induce several mitochondrial abnormalities such as low oxidative potential, high Ca2+-influx and changes in electron transport chain functions. TRPV4 is also involved in regulation of mitochondrial morphology, smoothness, and fusion-fission events. The C-terminal cytoplasmic region of TRPV4 can localize it to mitochondria and interacts with mitochondrial proteins including Hsp60, Mfn1 and Mfn2. Regulation of mitochondria by TRPV4 may contribute to previously uncharacterized mitochondria-specific functions observed in various cell types. This discovery may help to link TRPV4-mediated channelopathies with mitochondria-mediated diseases.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Kumar, A., Majhi, R. K., Acharya, T. K., Smalla, K.-H., Gundelfinger, E. D., Goswami, C.. 2018-05-25. TRPV4 interacts with mitochondrial proteins and acts as a mitochondrial structure-function regulator. https://doi.org/10.1101/330993

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Platycodin D2 Targets Vimentin to Suppress Fibroblast-Myofibroblast Transition: A Novel Therapeutic Strategy Against Pulmonary Fibrosis

Background Pulmonary fibrosis is a progressive lung disease characterized by excessive extracellular matrix deposition and irreversible decline in lung function with limited effective therapeutic targets. Vimentin, a type III intermediate filament protein, plays a critical role in fibroblast activation and fibrogenesis, representing a promising drug target. Methods Novel vimentin ligands were screened via virtual screening. SPR assay verified compound-vimentin binding affinity. CETSA and CD spectroscopy analyzed protein structural changes after compound binding. In vitro FMT model and in vivo bleomycin-induced pulmonary fibrosis model were used to assess antifibrotic effects, and mutagenesis assays identified key binding amino acid residues. Results Platycodin D2 (PD2) from Platycodon grandiflorus was identified as a novel high-affinity vimentin ligand (Kd = 392.8 nM). PD2 binds vimentin directly, alters its secondary structure and induces insoluble aggregation. It effectively inhibits TGF-{beta}1-induced FMT in vitro and mitigates bleomycin-induced pulmonary fibrosis in vivo, reducing collagen deposition and improving animal survival. Critically, mutagenesis validation confirmed that key residues (Glu138 in chain A, Glu132 and Glu143 in chain B, as well as Glu50 and Arg54 in chain C) are essential for this interaction. Conclusions Our findings establish PD2 as a novel pharmacological inducer of aberrant vimentin aggregation, presenting a distinct target-driven strategy for antifibrotic drug development.

cell biology↗

Receptor-proximal phosphoform organization precedes β2 integrin activation

Receptor signaling is often framed as protein recruitment after stimulation, but whether receptor-proximal environments are organized in composition and phosphorylation state beforehand remains unclear. We used CD18-APEX2 proximity labeling and a spatial membrane reference to quantify proteins and phosphosites near leukocyte {beta}2 integrins. At rest, receptors, adaptors and Rap GTPases were preferentially represented relative to several catalytic classes. Parent-protein correction revealed spatial phosphoform organization, with 32% of 4,564 phosphosites deviating significantly from the distribution center and 56% of proteins with multiple quantified sites showing divergence beyond measurement error. Sustained activation altered 31% of phosphosites while 95.9% of proteins remained equivalent within {+/-}0.5 log2 and spatial phosphoform organization largely persisted. Most phosphorylation responses were shared across both labeling environments, whereas receptor-preferential changes were dominated by phosphosites. These findings suggest that receptor signaling can regulate pre-existing molecular states without extensive protein redistribution.

cell biology↗

Diversification of budding yeast polarization dynamics after compensatory experimental evolution

Essential cellular processes evolve under strong selection, yet protein networks underlying conserved functions can vary substantially. To what extent evolution constrains the intracellular dynamics of proteins performing essential functions is currently largely unknown. Here, we characterize budding yeast polarization phenotypes along a previously established evolutionary recovery trajectory, compensating for the loss of near-essential polarity gene BEM1. Through quantitative live cell imaging, we show that loss of BEM1 weakens and destabilizes polarization. Surprisingly, in recovered evolved lineages, protein dynamics change significantly compared to the ancestor: most notably, presence of main regulator Cdc42-GTP is strongly decreased, while polarisome member Spa2 localizes more slowly into mobile foci. Although separate phenotypic characteristics are only weakly constrained, we find evidence of effective protein-independent localization modes, revealing signs of convergence along the evolutionary trajectory. Together, our results show that evolution can restore global cellular function without conserving microscopic organization, instead giving rise to novel molecular phenotypes.

cell biology↗