This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Yu, R. Articles by Hinkle, P. M. Search for Related Content PubMed PubMed Citation Articles by Yu, R. Articles by Hinkle, P. M.

Signal Transduction, Desensitization, and Recovery of Responses to Thyrotropin-Releasing Hormone after Inhibition of Receptor Internalization*

Department of Pharmacology and Physiology and the Cancer Center University of Rochester School of Medicine and Dentistry Rochester, New York 14642

Three independent methods were used to block internalization of the TRH receptor: cells were infected with vaccinia virus encoding a dominant negative dynamin, incubated in hypertonic sucrose, or stably transfected with a receptor lacking the C-terminal tail. Internalization was blocked in all three paradigms as judged by microscopy using a fluorescently labeled TRH agonist and biochemically. The initial inositol trisphosphate (IP₃) and Ca²⁺ responses to TRH were normal when internalization was inhibited. The IP₃ increase was sustained rather than transient, however, in cells expressing the truncated TRH receptor, implying that the C-terminal tail of the receptor may be important for uncoupling from phospholipase C. After withdrawal of TRH, cells were refractory to TRH until both ligand dissociation and resensitization of the receptor had occurred. When surface-bound TRH was removed by a mild acid wash, which did not impair receptor function, neither wild-type nor truncated receptors were able to generate full IP₃ responses for about 10 min. The rate of recovery was not altered by blocking internalization. Recovery of intracellular Ca²⁺ responses also depended on the rate of Ca²⁺ pool refilling. In summary, in the continued presence of TRH, phospholipase C activity declines quickly due to receptor uncoupling; this desensitization does not take place for the truncated receptor. After TRH is withdrawn, cells are refractory to TRH. Before cells can respond, TRH must dissociate and a resensitization step, which takes place on the plasma membrane and does not require the C-terminal tail of the receptor, must occur.

This article has been cited by other articles:

				B. W. Jones, G. J. Song, E. K. Greuber, and P. M. Hinkle Phosphorylation of the Endogenous Thyrotropin-releasing Hormone Receptor in Pituitary GH3 Cells and Pituitary Tissue Revealed by Phosphosite-specific Antibodies J. Biol. Chem., April 27, 2007; 282(17): 12893 - 12906. [Abstract] [Full Text] [PDF]

				P.-Y. Deng, J. E. Porter, H.-S. Shin, and S. Lei Thyrotropin-releasing hormone increases GABA release in rat hippocampus J. Physiol., December 1, 2006; 577(2): 497 - 511. [Abstract] [Full Text] [PDF]

				B. W. Jones and P. M. Hinkle {beta}-Arrestin Mediates Desensitization and Internalization but Does Not Affect Dephosphorylation of the Thyrotropin-releasing Hormone Receptor J. Biol. Chem., November 18, 2005; 280(46): 38346 - 38354. [Abstract] [Full Text] [PDF]

				G. J. Song and P. M. Hinkle Regulated Dimerization of the Thyrotropin-Releasing Hormone Receptor Affects Receptor Trafficking But Not Signaling Mol. Endocrinol., November 1, 2005; 19(11): 2859 - 2870. [Abstract] [Full Text] [PDF]

				L. B. Cook and P. M. Hinkle Fate of Internalized Thyrotropin-Releasing Hormone Receptors Monitored with a Timer Fusion Protein Endocrinology, July 1, 2004; 145(7): 3095 - 3100. [Abstract] [Full Text] [PDF]

				A. C. Hanyaloglu, R. M. Seeber, T. A. Kohout, R. J. Lefkowitz, and K. A. Eidne Homo- and Hetero-oligomerization of Thyrotropin-releasing Hormone (TRH) Receptor Subtypes. DIFFERENTIAL REGULATION OF beta -ARRESTINS 1 AND 2 J. Biol. Chem., December 20, 2002; 277(52): 50422 - 50430. [Abstract] [Full Text] [PDF]

				C.-C. Zhu, L. B. Cook, and P. M. Hinkle Dimerization and Phosphorylation of Thyrotropin-releasing Hormone Receptors Are Modulated by Agonist Stimulation J. Biol. Chem., July 26, 2002; 277(31): 28228 - 28237. [Abstract] [Full Text] [PDF]

				T. K. Graves, S. Patel, P. S. Dannies, and P. M. Hinkle Misfolded growth hormone causes fragmentation of the Golgi apparatus and disrupts endoplasmic reticulum-to-Golgi traffic J. Cell Sci., March 12, 2002; 114(20): 3685 - 3694. [Abstract] [Full Text] [PDF]

				H. A. W. Tawfeek, F. Qian, and A. B. Abou-Samra Phosphorylation of the Receptor for PTH and PTHrP Is Required for Internalization and Regulates Receptor Signaling Mol. Endocrinol., January 1, 2002; 16(1): 1 - 13. [Abstract] [Full Text] [PDF]

				J. Smith, R. Yu, and P. M. Hinkle Activation of MAPK by TRH Requires Clathrin-Dependent Endocytosis and PKC but Not Receptor Interaction with {beta}-Arrestin or Receptor Endocytosis Mol. Endocrinol., September 1, 2001; 15(9): 1539 - 1548. [Abstract] [Full Text] [PDF]

				A. Vallentin, C. Prevostel, T. Fauquier, X. Bonnefont, and D. Joubert Membrane Targeting and Cytoplasmic Sequestration in the Spatiotemporal Localization of Human Protein Kinase C alpha J. Biol. Chem., February 25, 2000; 275(8): 6014 - 6021. [Abstract] [Full Text] [PDF]

				J. S. L. Parker and C. R. Parrish Cellular Uptake and Infection by Canine Parvovirus Involves Rapid Dynamin-Regulated Clathrin-Mediated Endocytosis, Followed by Slower Intracellular Trafficking J. Virol., February 15, 2000; 74(4): 1919 - 1930. [Abstract] [Full Text]

				B. F. O’Dowd, D. K. Lee, W. Huang, T. Nguyen, R. Cheng, Y. Liu, B. Wang, M. C. Gershengorn, and S. R. George TRH-R2 Exhibits Similar Binding and Acute Signaling but Distinct Regulation and Anatomic Distribution Compared with TRH-R1 Mol. Endocrinol., January 1, 2000; 14(1): 183 - 193. [Abstract] [Full Text]

				A. Heding, M. Vrecl, A. C. Hanyaloglu, R. Sellar, P. L. Taylor, and K. A. Eidne The Rat Gonadotropin-Releasing Hormone Receptor Internalizes via a {beta}-Arrestin-Independent, but Dynamin-Dependent, Pathway: Addition of a Carboxyl-Terminal Tail Confers {beta}-Arrestin Dependency Endocrinology, January 1, 2000; 141(1): 299 - 306. [Abstract] [Full Text] [PDF]

				M. Blomenröhr, A. Heding, R. Sellar, R. Leurs, J. Bogerd, K. A. Eidne, and G. B. Willars Pivotal Role for the Cytoplasmic Carboxyl-Terminal Tail of a Nonmammalian Gonadotropin-Releasing Hormone Receptor in Cell Surface Expression, Ligand Binding, and Receptor Phosphorylation and Internalization Mol. Pharmacol., December 1, 1999; 56(6): 1229 - 1237. [Abstract] [Full Text]

				G. B. Willars, A. Heding, M. Vrecl, R. Sellar, M. Blomenrohr, S. R. Nahorski, and K. A. Eidne Lack of a C-terminal Tail in the Mammalian Gonadotropin-releasing Hormone Receptor Confers Resistance to Agonist-dependent Phosphorylation and Rapid Desensitization J. Biol. Chem., October 15, 1999; 274(42): 30146 - 30153. [Abstract] [Full Text] [PDF]

				P. Sarret, D. Nouel, C. Dal Farra, J.-P. Vincent, A. Beaudet, and J. Mazella Receptor-mediated Internalization Is Critical for the Inhibition of the Expression of Growth Hormone by Somatostatin in the Pituitary Cell Line AtT-20 J. Biol. Chem., July 2, 1999; 274(27): 19294 - 19300. [Abstract] [Full Text] [PDF]

				R. Yu and P. M. Hinkle Rapid Turnover of Calcium in the Endoplasmic Reticulum during Signaling. STUDIES WITH CAMELEON CALCIUM INDICATORS J. Biol. Chem., July 28, 2000; 275(31): 23648 - 23653. [Abstract] [Full Text] [PDF]

				K. M. Kroeger, A. C. Hanyaloglu, R. M. Seeber, L. E. C. Miles, and K. A. Eidne Constitutive and Agonist-dependent Homo-oligomerization of the Thyrotropin-releasing Hormone Receptor. DETECTION IN LIVING CELLS USING BIOLUMINESCENCE RESONANCE ENERGY TRANSFER J. Biol. Chem., April 13, 2001; 276(16): 12736 - 12743. [Abstract] [Full Text] [PDF]