Merck
CN
  • Dimeric Ube2g2 simultaneously engages donor and acceptor ubiquitins to form Lys48-linked ubiquitin chains.

Dimeric Ube2g2 simultaneously engages donor and acceptor ubiquitins to form Lys48-linked ubiquitin chains.

The EMBO journal (2013-12-25)
Weixiao Liu, Yongliang Shang, Yan Zeng, Chao Liu, Yanchang Li, Linhui Zhai, Pan Wang, Jizhong Lou, Ping Xu, Yihong Ye, Wei Li
ABSTRACT

Cellular adaptation to proteotoxic stress at the endoplasmic reticulum (ER) depends on Lys48-linked polyubiquitination by ER-associated ubiquitin ligases (E3s) and subsequent elimination of ubiquitinated retrotranslocation products by the proteasome. The ER-associated E3 gp78 ubiquitinates misfolded proteins by transferring preformed Lys48-linked ubiquitin chains from the cognate E2 Ube2g2 to substrates. Here we demonstrate that Ube2g2 synthesizes linkage specific ubiquitin chains by forming an unprecedented homodimer: The dimerization of Ube2g2, mediated primarily by electrostatic interactions between two Ube2g2s, is also facilitated by the charged ubiquitin molecules. Mutagenesis studies show that Ube2g2 dimerization is required for ER-associated degradation (ERAD). In addition to E2 dimerization, we show that a highly conserved arginine residue in the donor Ube2g2 senses the presence of an aspartate in the acceptor ubiquitin to position only Lys48 of ubiquitin in proximity to the donor E2 active site. These results reveal an unanticipated mode of E2 self-association that allows the E2 to effectively engage two ubiquitins to specifically synthesize Lys48-linked ubiquitin chains.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
L-Lysine, crystallized, ≥98.0% (NT)
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L-Lysine, ≥98% (TLC)
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L-Lysine, Vetec, reagent grade, ≥98%
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L-Lysine monohydrochloride, BioUltra, ≥99.5% (AT)
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L-Lysine monohydrochloride, reagent grade, ≥98% (HPLC)
Sigma-Aldrich
L-Lysine monohydrochloride, from non-animal source, meets EP, JP, USP testing specifications, suitable for cell culture, 98.5-101.0%
Supelco
L-Lysine monohydrochloride, Pharmaceutical Secondary Standard; Certified Reference Material
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L-Lysine monohydrochloride, certified reference material, TraceCERT®, Manufactured by: Sigma-Aldrich Production GmbH, Switzerland
Supelco
L-Lysine Acetate, Pharmaceutical Secondary Standard; Certified Reference Material