title: RING E3-Catalyzed E2 Self-Ubiquitination Attenuates the Activity of Ube2E Ubiquitin-Conjugating Enzymes.
abstract: Ubiquitination of a target protein is accomplished through sequential actions of the E1, E2s, and the E3s. E2s dictate the modification topology while E3 ligases confer substrate specificity and recruit the cognate E2. Human genome codes for ~35 different E2 proteins; all of which contain the characteristic ubiquitin-conjugating UBC core domain sufficient for catalysis. Many of these E2 enzymes also have N- or C-terminal extensions; roles of which are not very well understood. We show that the N-terminal extension of Ube2E1 undergoes intramolecular auto-ubiquitination. This self-ubiquitination activity is enhanced in the presence of interacting RING E3 ligases and results in a progressive attenuation of the E2 activity toward substrate/E3 modification. We also find that the N-terminal ubiquitination sites are conserved in all the three Ube2Es and replacing them with arginine renders all three full-length Ube2Es equally active as their core UBC domains. Based on these results, we propose that E3-catalyzed self-ubiquitination acts as a key regulatory mechanism that controls the activity of Ube2E class of ubiquitin E2s.
authors.affiliation: Department of Biochemistry, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India.
authors.forename: Prerana Agarwal
authors.initials: PA
authors.lastname: Banka
authors.affiliation: Department of Biochemistry, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India.
authors.forename: Adaitya Prasad
authors.initials: AP
authors.lastname: Behera
authors.affiliation: Department of Biochemistry, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India.
authors.forename: Sayani
authors.initials: S
authors.lastname: Sarkar
authors.affiliation: Department of Biochemistry, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India. Electronic address: ajit@jcbose.ac.in.
authors.forename: Ajit B
authors.initials: AB
authors.lastname: Datta
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D002384:Catalysis; D017124:Conserved Sequence; D006801:Humans; D008239:Lysine / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D044763:Ubiquitin-Conjugating Enzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D009687:Nuclear Proteins; C114070:RNF4 protein, human; D014157:Transcription Factors; C097309:UBE2D2 protein, human; C489963:UBE2E1 protein, human; D044763:Ubiquitin-Conjugating Enzymes; D008239:Lysine
keywords: Ube2D; Ube2E1; enzyme activity regulation; intramolecular ubiquitination; ubiquitin-conjugating enzymes