In vitro , phosphorylation of a protein fragment ( 539 706 ) from __SP__ __NODE__ protein to a phosphorylated ( S629 ) protein fragment ( 539 706 ) from __SP__ __NODE__ protein decreases phosphorylation of a protein fragment ( 539 706 ) from __SP__ __NODE__ protein to a phosphorylated ( S629 S639 ) protein fragment ( 539 706 ) from __SP__ __NODE__ protein that is increased by active __NODE__ protein .