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Cross-talk between Carboxypeptidase M and the Kinin B1 Receptor Mediates a New Mode of G Protein-coupled Receptor Signaling

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journal contribution
posted on 14.11.2013, 00:00 by Xianming Zhang, Fulong Tan, Viktor Brovkovych, Yongkang Zhang, Randal A. Skidgel
G protein-coupled receptor (GPCR) signaling is affected by formation of GPCR homo-or heterodimers, but GPCR regulation by other cell surface proteins is not well understood. We reported that the kinin B1 receptor (B1R) heterodimerizes with membrane carboxypeptidase M (CPM), facilitating receptor signaling via CPM-mediated conversion of bradykinin or kallidin to des-Arg kinin B1R agonists. Here, we found that a catalytically inactive CPM mutant that still binds substrate (CPM-E264Q) also facilitates efficient B1R signaling by B2 receptor agonists bradykinin or kallidin. This response required co-expression of B1R and CPM-E264Q in the same cell, was disrupted by antibody that dissociates CPM from B1R, and was not found with a CPM-E264Q-B1R fusion protein. An additional mutation that reduced the affinity of CPM for C-terminal Arg and increased the affinity for C-terminal Lys inhibited the B1R response to bradykinin (with C-terminal Arg) but generated a response to Lys(9)-bradykinin. CPM-E264Q-mediated activation of B1Rs by bradykinin resulted in increased intramolecular fluorescence resonance energy transfer (FRET) in a B1R FRET construct, similar to that generated directly by a B1R agonist. In cytokine-treated human lung microvascular endothelial cells, disruption of B1R-CPM heterodimers inhibited B1R-dependent NO production stimulated by bradykinin and blocked the increased endothelial permeability caused by treatment with bradykinin and pyrogallol (a superoxide generator). Thus, CPM and B1Rs on cell membranes form a critical complex that potentiates B1R signaling. Kinin peptide binding to CPM causes a conformational change in the B1R leading to intracellular signaling and reveals a new mode of GPCR activation by a cell surface peptidase.

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Funding

This work was supported by National Institutes of Health Grants DK41431 and HL60678.

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Publisher Statement

This research was originally published in Journal of Biological Chemistry. Zhang, X. M. Tan, F. L. Brovkovych, V. Zhang, Y. K. Skidgel, R. A. Cross-talk between Carboxypeptidase M and the Kinin B1 Receptor Mediates a New Mode of G Protein-coupled Receptor Signaling. Journal of Biological Chemistry. 2011. 286:18547-9258. © the American Society for Biochemistry and Molecular Biology

Citation

Zhang XM, Tan FL, Brovkovych V, Zhang YK, Skidgel RA. Cross-talk between Carboxypeptidase M and the Kinin B1 Receptor Mediates a New Mode of G Protein-coupled Receptor Signaling. Journal of Biological Chemistry. 2011;286(21):18547-18561 DOI: 10.1074/jbc.M110.214940

Publisher

American Society for Biochemistry and Molecular Biology

Language

en_US

issn

0021-9258

Issue date

01/05/2011

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