BUMPT cells as a model system for studying olfactory receptor signaling in renal epithelial cells.

Abstract

Olfactory receptors (ORs), a class of chemosensory G‐protein coupled receptors, are expressed in non‐sensory tissues (including kidney) where they serve to detect environmental cues. Renal ORs are expressed in cell types that lack components of the canonical OR signaling, Golfactory protein (Golf) and adenylate cyclase (AC3), indicating that they must signal via an unknown alternate signaling pathway involving a native G protein. We find that BUMPT, a mouse proximal tubule‐derived cell line, expresses 5 of the 9 known renal ORs including OR 691 (Olfr691; RT‐PCR). We also find that BUMPT cells, like native proximal tubule cells, do not express Golf or AC3 (RT‐PCR). Therefore, we used BUMPT to investigate the non‐canonical signaling mechanism of renal ORs. Using an unbiased degenerate PCR primer screen for Gα subunits, we identified Gα11, Gq and GαS in BUMPT cells (consistent with Gα subunits in the PT proteome). Gα11, Gq and GαS were subsequently confirmed to be expressed in both BUMPT and mouse kidney using gene‐specific primers. We have confirmed Gα11 and Gq protein expression in BUMPT cells and mouse kidney using an antibody that recognizes both; efforts to confirm the expression of GαS are in progress. We plan to test for physical association of Gα11, Gq and/or GαS to Olfr691, and investigate second messengers and downstream targets in BUMPT cells to elucidate the mechanism of renal OR signaling. Funding: NIDDK