Rhotekin-1 is a novel interacting protein and regulator of TRPC6 activity.

Abstract

Dysregulation of Transient Receptor Potential Canonical 6 (TRPC6) channel is associated with pathologies in which cell contraction is relevant. Therefore, understanding the molecular mechanisms underlying the regulation of actin cytoskeletal function by TRPC6 is important. Here, we observed that TRPC6 upregulates the activity of RhoA GTPase, affecting the organization and polymerization of the actin cytoskeleton and focal adhesion dynamics. Moreover, TRPC6 activity promoted cell contraction and migration. Using mass spectrometry, we identified Rhotekin-1 (RTKN-1), an effector of RhoA, as a new TRPC6-interacting protein. In addition, RTKN-1 expression prevented the effects of TRPC6 on cell contraction, migration, and spreading. Moreover, calcium imaging, TRPC6-jGCaMP8f recordings, and patch clamp assays showed that RTKN-1 acts as a negative regulator of TRPC6 activity by reducing the abundance of TRPC6 in the plasma membrane through a mechanism that depends on RhoA activation. In this context, we found that RTKN-1 expression increased the endocytosis of TRPC6 in the early endosome compartment. In summary, these results suggest RTKN-1 as a new interactor and regulator of TRPC6 activity through a novel mechanism involving the modulation of TRPC6 trafficking.