QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: mol.107.037747v1 72/2/429    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wang, Y. Articles by Xiang, Y. Search for Related Content PubMed PubMed Citation Articles by Wang, Y. Articles by Xiang, Y.

N-Ethylmaleimide-Sensitive Factor Regulates ₂ Adrenoceptor Trafficking and Signaling in Cardiomyocytes

Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois (Y.W., Y.X.); Program in Pharmaceutical Sciences and Pharmacogenomics and Department of Pharmaceutical Chemistry (B.L.), Department of Psychiatry and Department of Cellular and Molecular Pharmacology (M.V.Z.), University of California at San Francisco, San Francisco, California; and Department of Molecular and Cellular Physiology, Stanford Medical Center, Palo Alto, California (B.K.K.)

Recycling of G protein-coupled receptors determines the functional resensitization of receptors and is implicated in switching ₂ adrenoceptor (₂AR) G protein specificity in cardiomyocytes. The human ₂AR carboxyl end binds to the N-ethylmaleimide-sensitive factor (NSF), an ATPase integral to membrane trafficking machinery. It is interesting that the human ₂AR (h₂AR) carboxyl end pulled down NSF from mouse heart lysates, whereas the murine one did not. Despite this difference, both ₂ARs exhibited substantial agonist-induced internalization, recycling, and G_i coupling in cardiomyocytes. The h₂AR, however, displayed faster rates of agonist-induced internalization and recycling compared with the murine ₂AR (m₂AR) and a more profound G_i component in its contraction response. Replacing the m₂AR proline (-1) with a leucine generated a gain-of-function mutation, m₂AR-P417L, with a rescued ability to bind NSF, faster internalization and recycling than the m₂AR, and a significant enhancement in G_i signaling, which mimics the h₂AR. Selective disruption of the m₂AR-P417L binding to NSF inhibited the receptor coupling to G_i. Mean-while, inhibiting NSF with N-ethylmaleimide blocked the m₂AR recycling after agonist-induced endocytosis. Expressing the NSF-E329Q mutant lacking ATPase activity inhibited the m₂AR coupling to G_i in cardiomyocytes. Our results revealed a dual regulation on h₂AR trafficking and signaling by NSF through direct binding to cargo receptor and its ATPase activity and uncovered an unprecedented role for the receptor binding to NSF in regulating G protein specificity that has diverged between mouse and human ₂ARs.

Address correspondence to: Dr. Yang Xiang, Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, B523 Burrill Hall, MC-114, 407 S. Goodwin Avenue, Urbana, IL 61801. E-mail: kevinyx{at}uiuc.edu

This article has been cited by other articles:

				Y. Wang, V. De Arcangelis, X. Gao, B. Ramani, Y.-s. Jung, and Y. Xiang Norepinephrine- and Epinephrine-induced Distinct 2-Adrenoceptor Signaling Is Dictated by GRK2 Phosphorylation in Cardiomyocytes J. Biol. Chem., January 25, 2008; 283(4): 1799 - 1807. [Abstract] [Full Text] [PDF]