. "Any process that modulates the frequency, rate or extent of ubiquitin ligase activity, the catalysis of the reaction: ATP + ubiquitin + protein lysine = AMP + diphosphate + protein N-ubiquityllysine." . . . "regulation of ubiquitin-protein ligase activity" . "anaphase-promoting complex regulator" . "APC regulator" . "regulation of ubiquitin ligase activity" . "SCF complex regulator" . "ubiquitin ligase regulator" . "ubiquitin-protein ligase regulator" . . . . . . .