HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 287/6/C1667    most recent 00265.2004v1 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 ISI Web of Science 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 ISI Web of Science (11) Citing Articles via Google Scholar Google Scholar Articles by Tong, Q. Articles by Miller, B. A. Search for Related Content PubMed PubMed Citation Articles by Tong, Q. Articles by Miller, B. A.

RECEPTORS AND SIGNAL TRANSDUCTION

Erythropoietin-modulated calcium influx through TRPC2 is mediated by phospholipase C and IP₃R

¹Departments of Pediatrics and ²Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033; ³The Henry Hood Research Program, The Sigfried and Janet Weis Center for Research, The Geisinger Clinic, Danville, Pennsylvania 17822; ⁴Division of Cellular and Molecular Biology, Ontario Cancer Institute, Toronto, Ontario M5G 2M9, Canada; and ⁵Department of Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153

Submitted 2 June 2004 ; accepted in final form 18 August 2004

In the present study, we examined the mechanisms through which erythropoietin (Epo) activates the calcium-permeable transient receptor potential protein channel (TRPC)2. Erythroblasts were isolated from the spleens of phenylhydrazine-treated mice, and Epo stimulation resulted in a significant and dose-dependent increase in intracellular calcium concentration ([Ca²⁺]_i). This increase in [Ca²⁺]_i was inhibited by pretreatment with the phospholipase C (PLC) inhibitor U-73122 but not by the inactive analog U-73343, demonstrating the requirement for PLC activity in Epo-modulated Ca²⁺ influx in primary erythroid cells. To determine whether PLC is involved in the activation of TRPC2 by Epo, cell models were used to examine this interaction. Single CHO-S cells that expressed transfected Epo receptor (Epo-R) and TRPC2 were identified, and [Ca²⁺]_i was quantitated. Epo-induced Ca²⁺ influx through TRPC2 was inhibited by pretreatment with U-73122 or by downregulation of PLC1 by RNA interference. PLC activation results in the production of inositol 1,4,5-trisphosphate (IP₃), and TRPC2 has IP₃ receptor (IP₃R) binding sites. To determine whether IP₃R is involved in Epo-R signaling, TRPC2 mutants were prepared with partial or complete deletions of the COOH-terminal IP₃R binding domains. In cells expressing TRPC2 IP₃R binding mutants and Epo-R, no significant increase in [Ca²⁺]_i was observed after Epo stimulation. TRPC2 coassociated with Epo-R, PLC, and IP₃R, and the association between TRPC2 and IP₃R was disrupted in these mutants. Our data demonstrate that Epo-R modulates TRPC2 activation through PLC; that interaction of IP₃R with TRPC2 is required; and that Epo-R, TRPC2, PLC, and IP₃R interact to form a signaling complex.

transient receptor potential protein channels; erythropoietin receptor; calcium channels

This article has been cited by other articles:

				M. A. Kerenyi, F. Grebien, H. Gehart, M. Schifrer, M. Artaker, B. Kovacic, H. Beug, R. Moriggl, and E. W. Mullner Stat5 regulates cellular iron uptake of erythroid cells via IRP-2 and TfR-1 Blood, November 1, 2008; 112(9): 3878 - 3888. [Abstract] [Full Text] [PDF]

				F. Grebien, M. A. Kerenyi, B. Kovacic, T. Kolbe, V. Becker, H. Dolznig, K. Pfeffer, U. Klingmuller, M. Muller, H. Beug, et al. Stat5 activation enables erythropoiesis in the absence of EpoR and Jak2 Blood, May 1, 2008; 111(9): 4511 - 4522. [Abstract] [Full Text] [PDF]