부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.yexcr.2005.04.030 Byline: Adrienne Halupa (a)(b), Manprit Chohan (a)(b), Natalie H. Stickle (a)(b)(c), Bryan K. Beattie (a), Barbara A. Miller (e), Dwayne L. Barber (a)(b)(c)(d) Keywords: Erythropoietin; Phospholipase C[gamma]; Extracellular signal-regulated kinase; Signal transduction; Erythropoiesis; Hematopoietic signaling Abstract: Red blood cell development is primarily controlled by erythropoietin (EPO). Several studies have revealed the importance of EPO-R Y343 and Y479 for erythroid cell growth, differentiation, and survival. In order to isolate critical signaling proteins that bind to EPO-R, we initiated a Cloning of Ligand Target (COLT) screen using a murine embryonic day 16 phage library and a biotinylated EPO-R Y343 phosphopeptide. One of the clones isolated encodes Phospholipase C (PLC)[gamma]1. PLC[gamma]1 is rapidly tyrosine phosphorylated upon EPO stimulation and associates with EPO-R in an SH2-domain-dependent manner. Although PLC[gamma]1 bound EPO-R Y343, Y401, Y429, Y431, and Y479 in the COLT screen, PLC[gamma]1 required Y479 for association with EPO-R in Ba/F3-EPO-R cells. Studies have identified EPO-R Y479 as important for ERK activation. Since PI3-kinase binds EPO-R Y479, one group has suggested that ERK activation downstream of PI3-kinase accounts for the importance of this residue in EPO signaling. However, we show that inhibition of PI3-kinase does not abolish ERK activation. Furthermore, we demonstrate interaction of PLC[gamma]1 with Grb2 and SOS2. Hence, we have identified a novel adapter function for PLC[gamma]1 in EPO signaling in which recruitment of PLC[gamma]1 to EPO-R may lead to activation of the ERK pathway. Author Affiliation: (a) Division of Stem Cell and Developmetal Biology, Ontario Cancer Institute, University of Toronto, Toronto, Ontario, Canada M5G 2M9 (b) Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada M5G 2M9 (c) Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 2M9 (d) Department of Laboratory Medicine and Pathobiology, University Health Network, Toronto, Ontario, Canada M5G 2M9 (e) Department of Pediatrics, Milton S. Hershey Medical Center, PO Box 850, Hershey, PA 17033, USA Article History: Received 12 May 2004; Revised 29 April 2005