SGK1 mRNA and protein expression in human as well as in murine platelets and megakaryocytes. (A) Quantitative RT-PCR of mRNA encoding SGK1 in human platelets and HEK293 cells. (B) Western blot and confocal microscopy of SGK1 abundance in human platelets, nontransfected and ^S422DSGK1-transfected HEK293 cells. Red represents actin; and green, SGK1. Bar represents 5 μm. (C) Arithmetic mean ± SEM (n = 4) of mRNA encoding SGK1 in platelets from sgk1^−/− mice expressed in percentage of the respective value in platelets from sgk1^+/+ mice. ***P < .001. (D) Representative Western blot analysis of SGK1 protein abundance in platelets from sgk1^+/+ and sgk1^−/− mice. (E) Arithmetic mean ± SEM (n = 4) of mRNA encoding SGK1 in megakaryocytes from sgk1^−/− mice expressed in percentage of the respective value in megakaryocytes from sgk1^+/+ mice. ***P < .001. (F) Confocal microscopy of SGK1 protein abundance in megakaryocytes from sgk1^+/+ (top) and sgk1^−/− (bottom) mice. Red represents glycoprotein Ib; green, SGK1; and blue, nuclei. Bar represents 10 μm.