[HTML][HTML] Certain pairs of ubiquitin-conjugating enzymes (E2s) and ubiquitin-protein ligases (E3s) synthesize nondegradable forked ubiquitin chains containing all …
It is generally assumed that a specific ubiquitin ligase (E3) links protein substrates to
polyubiquitin chains containing a single type of isopeptide linkage, and that chains
composed of linkages through Lys 48, but not through Lys 63, target proteins for
proteasomal degradation. However, when we carried out a systematic analysis of the types
of ubiquitin (Ub) chains formed by different purified E3s and Ub-conjugating enzymes (E2s),
we found, using Ub mutants and mass spectrometry, that the U-box E3, CHIP, and Ring …
polyubiquitin chains containing a single type of isopeptide linkage, and that chains
composed of linkages through Lys 48, but not through Lys 63, target proteins for
proteasomal degradation. However, when we carried out a systematic analysis of the types
of ubiquitin (Ub) chains formed by different purified E3s and Ub-conjugating enzymes (E2s),
we found, using Ub mutants and mass spectrometry, that the U-box E3, CHIP, and Ring …