INTRINSIC NUCLEOSIDE DIPHOSPHATE KINASE-LIKE ACTIVITY AS A NOVEL FUNCTION OF 14-3-3-PROTEINS

14-3-3 proteins play a role in many cellular functions as molecular ch aperone and adapter proteins: they bind to and modulate several protei ns involved in cell proliferation and differentiation, and also functi on ATP-dependently in targeting of precursors to mitochondria, We show here that 14-3-3 purified from a human lymphoblastoma and also its re combinant tau isoform exhibited intrinsic nucleoside diphosphate (NDP) kinase-like activity, 14-3-3 proteins preferentially catalyzed the tr ansfer of the gamma-phosphate group from ATP, dATP or dGTP to all nucl eoside diphosphates and this transfer involved acid-labile phosphoenzy me intermediates, They also simultaneously catalyzed the reverse react ion of ATP hydrolysis. These properties of 14-3-3 are similar to those of NDP kinase, but not to those of adenylate kinase. (C) 1997 Federat ion of European Biochemical Societies.