Translocation of TRPV2 Channel Induced by Focal Administration of Mechanical Stress.

The effect of focal mechanical stress on the localization of TRPV2 was investigated in HT1080 cells, where only mRNA for TRPV2 was detected among members of the TRPV channel family. Mechanical stress was applied by adding negative pressure using a glass pipette. When focal mechanical stress was applied, subplasma membrane Ca(2+) concentration ([Ca(2+)]s) was increased beneath the pipette, which propagated throughout the cell. The increase in [Ca(2+)]s was blocked by ruthenium red or by knocking down TRPV2. Elevation of [Ca(2+)]s was not observed by removal of extracellular Ca(2+), by an addition of a phosphatidylinositol 3-kinase inhibitor LY29034, and by transfection of dominant-negative Rac. In cells expressing GFP-TRPV2 and RFP-Akt, administration of focal mechanical stress induced accumulation of GFP-TRPV2 beneath the pipette. RFP-Akt was also accumulated to the same site. Gadolinium blocked the elevation of [Ca(2+)]s induced by focal mechanical stress and also attenuated accumulation of TRPV2. When GFP-TRPV1, GFP-TRPV3, GFP-TRPV4, GFP-TRPV5, or GFP-TRPV6 was transfected ectopically in HT1080 cells, only GFP-TRPV4 was accumulated beneath the pipette in response to the focal mechanical stress. These results indicate that TRPV2 translocates to the site receiving a focal mechanical stress and increases [Ca(2+)]s.