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Symmetric signaling by an asymmetric 1 erythropoietin : 2 erythropoietin receptor complex

Thesis (M. Eng.)--Massachusetts Institute of Technology, Biological Engineering Division, 2008. / Includes bibliographical references (p. 43-46). / One erythropoietin molecule binds asymmetrically to two identical receptor monomers via erythropoietin site 1 and site 2, although it is unclear how asymmetry affects receptor activation and signaling. Here we report the computational design and experimental validation of two mutant erythropoietin receptors: one that binds only to erythropoietin site 1 but not site 2, and one that binds only to site 2 but not site 1. Expression of either mutant receptor alone in Ba/F3 cells cannot elicit a signal in response to erythropoietin, but when co-expressed, there is a proliferative response and activation of the JAK2 Stat5 signaling pathway. A truncated erythropoietin receptor with only one cytosolic tyrosine (Y343), on only one receptor monomer is sufficient for signaling in response to erythropoietin, regardless of the monomer on which it is located. The same results apply to having only one conserved juxtamembrane hydrophobic L253 or W258 residue, essential for JAK2 activation, in the full-length receptor dimer. We conclude that despite asymmetry in the ligand-receptor dimer interaction, both sides are competent for signaling, and we suggest that the receptors signal equally. / by Yingxin Zhang. / M.Eng.

Identiferoai:union.ndltd.org:MIT/oai:dspace.mit.edu:1721.1/45211
Date January 2008
CreatorsZhang, Yingxin
ContributorsHarvey F. Lodish., Massachusetts Institute of Technology. Biological Engineering Division., Massachusetts Institute of Technology. Biological Engineering Division.
PublisherMassachusetts Institute of Technology
Source SetsM.I.T. Theses and Dissertation
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Format46 p., application/pdf
RightsMIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission., http://dspace.mit.edu/handle/1721.1/7582

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