title: Tissue kallikrein stimulates Ca(2+) reabsorption via PKC-dependent plasma membrane accumulation of TRPV5.
abstract: The transient receptor potential vanilloid 5 (TRPV5) channel determines urinary Ca(2+) excretion, and is therefore critical for Ca(2+) homeostasis. Interestingly, mice lacking the serine protease tissue kallikrein (TK) exhibit robust hypercalciuria comparable to the Ca(2+) leak in TRPV5 knockout mice. Here, we delineated the molecular mechanism through which TK stimulates Ca(2+) reabsorption. Using TRPV5-expressing primary cultures of renal Ca(2+)-transporting epithelial cells, we showed that TK activates Ca(2+) reabsorption. The stimulatory effect of TK was mimicked by bradykinin (BK) and could be reversed by application of JE049, a BK receptor type 2 antagonist. A cell permeable analog of DAG increased TRPV5 activity within 30 min via protein kinase C activation of the channel since mutation of TRPV5 at the putative PKC phosphorylation sites S299 and S654 prevented the stimulatory effect of TK. Cell surface labeling revealed that TK enhances the amount of wild-type TRPV5 channels, but not of the TRPV5 S299A and S654A mutants, at the plasma membrane by delaying its retrieval. In conclusion, TK stimulates Ca(2+) reabsorption via the BK-activated PLC/DAG/PKC pathway and the subsequent stabilization of the TRPV5 channel at the plasma membrane.
authors.affiliation: Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Dimitra
authors.initials: D
authors.lastname: Gkika
authors.forename: Catalin N
authors.initials: CN
authors.lastname: Topala
authors.forename: Qing
authors.initials: Q
authors.lastname: Chang
authors.forename: Nicolas
authors.initials: N
authors.lastname: Picard
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Thébault
authors.forename: Pascal
authors.initials: P
authors.lastname: Houillier
authors.forename: Joost G J
authors.initials: JG
authors.lastname: Hoenderop
authors.forename: René J M
authors.initials: RJ
authors.lastname: Bindels
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D001920:Bradykinin / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D065094:Bradykinin B2 Receptor Antagonists; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects / Q000235:genetics; D006801:Humans; D007610:Kallikreins / Q000378:metabolism*; D007684:Kidney Tubules / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D020125:Mutation, Missense; D010091:Oximes / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011817:Rabbits; D043782:Receptor, Bradykinin B2 / Q000819:agonists / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D050916:TRPV Cation Channels / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D065094:Bradykinin B2 Receptor Antagonists; D015220:Calcium Channels; D010091:Oximes; D043782:Receptor, Bradykinin B2; D050916:TRPV Cation Channels; C492240:Trpv5 protein, mouse; D014665:Vasodilator Agents; C507900:diaminoglyoxime; C065679:icatibant; D011493:Protein Kinase C; D007610:Kallikreins; D001920:Bradykinin; D002118:Calcium