Abstract

Protein phosphorylation plays a critical role in the signaling pathways regulating water transport in kidney collecting duct. A central mediator in this process is the hormone arginine vasopressin (AVP), which regulates phosphorylation of the water channel aquaporin‐2 (AQP2), although the exact mechanisms are not fully understood. Here we utilized a multiplexed, isotopic label‐based quantitative phosphoproteomic approach in order to explore the temporal dynamics of phosphorylation events triggered by vasopressin across multiple timepoints. Briefly, rat inner medullary collecting duct (IMCD) samples were incubated in the presence or absence of 1nM AVP for 0.5, 2, 5, and 15 min (n=3). Each sample was labeled with a different iTRAQ reagent, mixed and processed for shotgun phosphoproteomic analysis. Of the 12,533 phosphopeptides identified, 3,298 were found in at least 2 out of 3 time courses and had …