Role of the cAMP/PKA signaling cascade in vasopressin‐induced trafficking of TRPC3 channels in principal cells of the collecting duct

Abstract

The transient receptor potential channels TRPC3 and TRPC6 are abundantly expressed in principal cells of the collecting duct (CD) along with the water channel, aquaporin‐2 (AQP2). All three channels localize to intracellular vesicles, but upon stimulation with arginine‐vasopressin (AVP), TRPC3 and AQP2 translocate to the apical membrane. In the present study, the effect of various activators and inhibitors of the adenylyl cyclase (AC)/cAMP/PKA signaling cascade on channel trafficking was examined in principal cells of the CD. Translocation of AQP2 and TRPC3 (but not TRPC6) was stimulated by [deamino‐Cys1, D‐Arg8]‐vasopressin (dDAVP), a specific V2‐receptor agonist, and blocked by [adamantaneacetyl1, O‐Et‐D‐Tyr2, Val4, Aminobutyryl6, Arg8,9]‐vasopressin (AEAVP), a specific V2 receptor antagonist. Translocation was also activated by forskolin, a direct activator of AC, or by di‐butyryl‐cAMP, a membrane‐permeable cAMP analog. AVP‐, dDAVP‐, and forskolin‐induced translocation was blocked by SQ22536 and H89, specific inhibitors of AC and PKA, respectively. Translocation stimulated by di‐butyryl‐cAMP was unaffected by AEAVP, but could be blocked by H89. Taken together, these results demonstrate that AVP stimulation of V2‐receptors in principal cells of the CD causes translocation of TRPC3 to the apical membrane via stimulation of the AC/cAMP/PKA signaling cascade. Supported in part by HL097355.