TRANSLATIONAL CONTROL MEDIATES THE DEVELOPMENTAL REGULATION OF THE TRYPANOSOMA BRUCEI NRK PROTEIN KINASE

摘要: The expression and function of eukaryotic protein kinases is highly regulated, primarily through transcriptional post-translational processes. In this report we demonstrate an unusual mechanism for controlling kinase function, translational control. Trypanosoma brucei Nrk loci encode predicted kinases. Here show that has serine-threonine activity examine the during parasite development. While transcripts were previously found to be constitutively expressed throughout life cycle, now find stage-regulated. Immunoblot analysis revealed dramatically increased as parasites differentiated from proliferative slender bloodforms non-proliferative stumpy bloodforms. Procyclic form organisms moderate levels Nrk. Analysis demonstrated it too was highest in Metabolic labeling pulse-chase accumulation indicated abundance controlled at level biosynthesis rather than turnover. All mRNA contained poly(A)+ fraction, 5' ends transcript same each developmental stage. Thus, under strict regulation enzymes within trypanosome cycle suggests may play a role differentiation.