RT Book, Section A1 Kaushansky, Kenneth A2 Kaushansky, Kenneth A2 Lichtman, Marshall A. A2 Prchal, Josef T. A2 Levi, Marcel M. A2 Press, Oliver W. A2 Burns, Linda J. A2 Caligiuri, Michael SR Print(0) ID 1121089705 T1 Signal Transduction Pathways T2 Williams Hematology, 9e YR 2015 FD 2015 PB McGraw-Hill Education PP New York, NY SN 9780071833004 LK accessmedicine.mhmedical.com/content.aspx?aid=1121089705 RD 2024/03/29 AB SUMMARYMost external influences upon cells of any organ are mediated by biochemical and molecular mechanisms that are triggered by interactions with membrane, cytoplasmic, or nuclear receptors. Our understanding of the receptors and the intermediate molecules that couple them with cellular pathways that influence the proliferation, activation, differentiation, or survival of hematopoietic cells has expanded significantly. Proteins on the surface of blood cells that transmit vital information from the extracellular environment include single-pass, homodimeric, heterodimeric, and heterotrimeric transmembrane proteins that do, or do not, contain intrinsic kinase activity, but either way signal by inducing the tyrosine phosphorylation of a multitude of cytoplasmic proteins, seven transmembrane domain proteins that signal through G proteins, heterodimeric integrins that recruit large focal adhesions, and large families of heterodimeric proteins that induce serine and threonine phosphorylation. This chapter describes the receptors that influence blood cell production and function, the secondary mediators and the biochemical modifications they undergo to alert the cell to an external influence, the molecular mechanisms that allow for the coordination of multiple signals impacting a cell simultaneously, and the processes upon which they impact.