Erythropoietin stimulates nuclear localization of diacylglycerol and protein kinase C βII in B6SUt.EP cells

• Published in: Journal of lipid mediators and cell signalling Vol. 17; no. 3; pp. 135 - 150
• Main Authors: Mallia, Conrad M, Smith, Michelle, Clejan, Sanda, Beckman, Barbara S
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.1997
• Subjects: 1,2-Diacylglycerol; Animals; Biological Transport, Active - drug effects; Calcium-Calmodulin-Dependent Protein Kinases - metabolism; Cell Division - drug effects; Cell Line; Cell Nucleus - drug effects; Cell Nucleus - metabolism; Diglycerides - metabolism; Erythropoietin; Erythropoietin - pharmacology; Gene Expression - drug effects; Hematopoietic Stem Cells - cytology; Hematopoietic Stem Cells - drug effects; Hematopoietic Stem Cells - metabolism; Isoenzymes - metabolism; Kinetics; Mice; Models, Biological; Protein kinase C; Protein Kinase C - metabolism; Protein Kinase C beta; Recombinant Proteins; Signal Transduction; Subcellular Fractions - metabolism; Erythropoietin; 1,2-Diacylglycerol; Protein kinase C
• ISSN: 0929-7855
• DOI: 10.1016/S0929-7855(97)00027-8

Erythropoietin (EPO) is a hormone, as well as a hematopoietic growth factor, that specifically regulates the proliferation and differentiation of erythroid progenitor cells. Although the membrane-bound receptor for EPO has no intrinsic kinase activity, it triggers the activation of protein kinases via phospholipases A 2, C, and D. A cascade of serine and threonine kinases, including Raf-1, MAP kinase and protein kinase C (PKC) is activated following tyrosine phosphorylation. In this study, we have examined whether changes in nuclear PKC and 1,2-diacylglycerol (DAG) are induced following EPO treatment of the murine target cell line, B6SUt.EP. Western blot analysis using isoform-specific antibodies demonstrated the presence of PKC βII, but not PKC α, βI, γ, ε, δ, η, or ζ in the nuclei of cells stimulated with EPO. The increase in nuclear βII levels was accompanied by an immediate rise in DAG mass levels with both of the increases peaking by 1 min. These rapid increases in nuclear DAG and PKC βII expression suggest a mechanism for EPO-induced changes in gene expression necessary for cell proliferation.