title: Erythrocyte spectrin is an E2 ubiquitin conjugating enzyme.
abstract: The involvement of red blood cell spectrin in the ubiquitination process was studied. Spectrin was found to form two ubiquitin-associated derivatives, a DTT-sensitive ubiquitin adduct and a DTT-insensitive conjugate, characteristic intermediate and final products of the ubiquitination reaction cascade. In addition to spectrin and ubiquitin, ubiquitin-activating enzyme (E1) and ATP were necessary and sufficient to form both the spectrin-ubiquitin adduct and conjugate. No exogenous ubiquitin-conjugating (E2) or ligase (E3) activities were required, suggesting that erythrocyte spectrin is an E2 ubiquitin-conjugating enzyme able to target itself. Both ubiquitin adduct and conjugate were linked to the alpha subunit of spectrin, suggesting that the ubiquitin-conjugating (UBC) domain and its target regions reside on the same subunit.
authors.affiliation: Department of Cell Biology and Neuroscience, University of South Alabama College of Medicine, Mobile, Alabama 36688, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Kakhniashvili
authors.forename: T
authors.initials: T
authors.lastname: Chaudhary
authors.forename: W E
authors.initials: WE
authors.lastname: Zimmer
authors.forename: F A
authors.initials: FA
authors.lastname: Bencsath
authors.forename: I
authors.initials: I
authors.lastname: Jardine
authors.forename: S R
authors.initials: SR
authors.lastname: Goodman
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000378:metabolism*; D006801:Humans; D008025:Ligases / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000737:chemistry; D013049:Spectrin / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D044763:Ubiquitin-Conjugating Enzymes; D014452:Ubiquitins / Q000378:metabolism*
chemical_list: D010446:Peptide Fragments; D014452:Ubiquitins; D013049:Spectrin; D000255:Adenosine Triphosphate; D044763:Ubiquitin-Conjugating Enzymes; D008025:Ligases