Identification of functionally important residues of human thrombopoietin.

The Journal of Biological Chemistry
H ParkH J Hong

Abstract

Thrombopoietin (TPO) is a megakaryocyte growth and differentiation factor. It consists of a characteristic two domain structure. The amino-terminal domain of TPO has a sequence homology with erythropoietin and is required for the binding and activation of its receptor c-Mpl. To determine the functionally important regions interacting with its receptor, a series of site-directed mutants of TPO were constructed based on a three-dimensional model of the amino-terminal domain. Two strategies of mutagenesis were employed: 1) nonnative N-linked glycosylation scan of 12 residues predicted to be on the surface, and 2) alanine replacement scan of mostly charged 44 amino acid residues. Each TPO mutein was transiently expressed in COS7 cells, and the specific bioactivity of the TPO protein secreted into the culture medium was measured using a recombinant BaF3 cell line expressing human c-Mpl. Four alanine substitutions at Arg10, Pro42, Glu50, and Lys138 nearly or completely abolished the activity, whereas the mutation at Arg14 slightly decreased the activity, suggesting that these residues are functionally important in interacting with its receptor. These residues mapped to helix A, loop AB, and helix D. Sequence comparison between human ...Continue Reading

References

Jan 1, 1977·Proceedings of the National Academy of Sciences of the United States of America·D D Pless, W J Lennarz
Jul 1, 1990·Trends in Biochemical Sciences·D CosmanC J March
Sep 1, 1990·Proceedings of the National Academy of Sciences of the United States of America·J F Bazan
Jun 9, 1995·Gene·K OgamiH Miyazaki
Jun 1, 1994·Molecular and Cellular Biology·S S WatowichH F Lodish
Jun 16, 1994·Nature·F WendlingW Vainchenker
Mar 1, 1996·Proteins·J A CaravellaW G Richards
Aug 15, 1997·The Journal of Biological Chemistry·K H PearceJ A Wells

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Citations

Oct 10, 1998·Stem Cells·T KatoH Miyazaki
Sep 30, 2000·Stem Cells·T KatoH Miyazaki
Dec 26, 2001·Cytokine & Growth Factor Reviews·Amy E GeddisKenneth Kaushansky
Jun 18, 1999·Annals of the New York Academy of Sciences·D D Cooper, G J Spangrude
Feb 11, 2004·Proceedings of the National Academy of Sciences of the United States of America·Michael D FeeseRyota Kuroki
Feb 5, 2008·Experimental Hematology·Petr BartunekMichal Dvorak
Mar 31, 1999·Baillière's Clinical Haematology·A E von dem BorneM de Haas
Oct 7, 2011·Cytokine & Growth Factor Reviews·Anna TarasovaDavid Winkler
Nov 12, 2015·BioMed Research International·Ondrej Svoboda, Petr Bartunek
May 30, 2014·Blood·Ondřej SvobodaPetr Bartůněk

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