Protein phosphorylation in astrocytes mediated by protein kinase C: comparison with phosphorylation by cyclic AMP-dependent protein kinase.

摘要: : The protein kinase C activator, phorbol 12-myris-tate 13-acetate (PMA), has been found recently to transform cultured astrocytes from flat, polygonal cells into stellate-shaped, process-bearing cells. Studies were conducted determine the effect of PMA on phosphorylation in and compare this pattern with that elicited by dibutyryl cyclic AMP (dbcAMP), an activator AMP-dependent which also affects astrocyte morphology. Exposure increased amount of32P incorporation several phosphoproteins, including two cytosolic proteins molecular weights 30,000 (pI 5.5 5.7), acidic 80,000 weight 4.5) present both membrane fractions, cytoskeletal 60,000 5.3) 55,000 5.6), identified as vimentin glial fibrillary protein, respectively. Effects not observed depleted C. In contrast PMA, treatment dbcAMP decreased 32P protein. Like 60,000, 30,000, although magnitude was different. still results suggest via activation C, can alter a number astrocytes, some these same phosphoproteins are phosphorylated mechanisms.