Protein Kinase C in Erythroleukaemia Cells: Temporal Variations in the Expression of the Alpha, Epsilon and Zeta Isoforms

Determinations of mRNA and enzyme protein analyses for the protein kinase C (PKC) isoforms, alpha, epsilon and zeta, representing the classical, novel and atypical groups, respectively, in murine erythroleukaemic (MEL) cells revealed the occurrence of cyclic behaviour in expression. Such rhythmicity was not apparent when multiple analyses using only a single time-point were considered; the importance of incorporating a time component into experimental design was demonstrated. On induction of differentiation over a period of five days with hexamethylene bisacetamide, changes in the patterns of expression of mRNA and protein were apparent, as compared with those of untreated, proliferating cells. Modulation of the dynamics of the various PKC isoforms may represent a regulatory mechanism for the control of a diversity of cellular functions.