Download Citation on ResearchGate | RING domain E3 ubiquitin ligases | E3 ligases confer specificity to ubiquitination by recognizing target substrates and. A ubiquitin ligase is a protein that recruits an E2 ubiquitin-conjugating enzyme that has been The RING-finger E3 ligases are the largest family and contain ligases such as the anaphase-promoting complex (APC) and the SCF complex. RING domain E3 ubiquitin ligases. The activity of most E3s is specified by a RING domain, which binds to an E2 approximately ubiquitin thioester and activates discharge of its ubiquitin cargo.


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Although the precise endocytic mechanism varies for different mammalian receptors, ubiquitylation by the CBL family of RING finger E3s has crucial roles in this process Acconcia et ring domain e3 ubiquitin ligases.

CBL family members modify the activated RTK with mono- or Klinked ubiquitin chains that — together with the direct recruitment of proteins to CBL itself — assemble a multi-protein complex that includes ubiquitin-binding domain UBD -containing proteins so-called ubiquitin receptors Swaminathan and Tsygankov, The exact role for RTK ubiquitylation by CBL in the initial receptor internalization step is unclear, but ongoing ubiquitylation of RTKs by this E3 ligase is necessary for correct downstream sorting and degradation of the signaling complex by the lysosome Marmor and Yarden, ; Williams and Urbe, Ubiquitylation, as well as deubiquitylation of components of the RTK complex and recruitment of ubiquitin-binding proteins, thus, have essential roles in the modulation of growth factor ring domain e3 ubiquitin ligases.

HECT and RING finger families of E3 ubiquitin ligases at a glance | Journal of Cell Science

Early discoveries regarding endocytosis and vacuolar targeting in yeast advanced our understanding of the mechanisms that are involved in the downregulation of proteins from the plasma membrane in mammalian cells. The NEDD4 isoforms in particular mediate ubiquitylation that leads to the cell-surface downregulation of transporters and receptors, such as the epithelial sodium channel ENaC Rotin and Kumar, ; Staub et al.

A common feature of the NEDD4 family is the presence of two to four double tryptophan residue WW domains in the N-terminal half of the molecule that recognize proline-containing so-called PY motifs on substrates Ring domain e3 ubiquitin ligases and Kumar, All of those ring domain e3 ubiquitin ligases are essential for gp78 function.

HRD1 has been implicated in arthropathies including rheumatoid arthritis Amano et al. Adding further complexity to ERAD pathways, gp78 can be targeted for degradation by autoubiquitylation and by ubiquitylation through HRD1 that — in turn — stabilizes gp78 substrates Ballar et al.

Of note, several CHIP substrates e. In ring domain e3 ubiquitin ligases, studies in yeast have implicated ring domain e3 ubiquitin ligases E3s in protein quality control within the cytosol as well as throughout the cell Bengtson and Joazeiro, ; Eisele and Wolf, ; Gardner et al.

IAP RING finger E3s and UPS in the intrinsic apoptosis pathway Chronic protein misfolding, as well as oxidative or genotoxic stress and developmental cues, can lead to apoptosis — another process during which E3s have crucial roles Vucic et al.

Ubiquitin ligase - Wikipedia

In the intrinsic apoptotic pathway, stimuli trigger release of cytochrome c from mitochondria, leading to formation of apoptosomes. These activate caspase 9, which — in turn — activates the effector ring domain e3 ubiquitin ligases 3 and 7 that mediate cell death.

X-chromosome-linked IAP XIAP binds to caspases 3, 7 and 9, directly blocks their catalytic activity and, additionally, regulates their protein levels through ubiquitylation and subsequent degradation Morizane et al. A key mediator of this is the hypoxia-inducible factor HIF family of transcription factors that induce transcription of genes involved in bioenergetics, cell growth and angiogenesis Kaelin and Ratcliffe, ; Majmundar et al.

RING domain E3 ubiquitin ligases. - PubMed - NCBI

Perspectives E3s have crucial roles in cellular homeostasis and development, and frequently contribute to pathophysiological states.

As our appreciation of the complexity of the ubiquitylation system increases, so do the number of questions regarding E3s, including their cellular functions, mechanisms of action and possible redundancy.

Whereas humans have — putative E3s, the Arabidopsis thaliana genome encodes over F-box proteins alone Gagne et ring domain e3 ubiquitin ligases. Whereas, intuitively, it makes sense that sessile organisms have more varied ways of adapting to their environments, these numbers are still extraordinary.

RING domain E3 ubiquitin ligases.

In addition to the ligase domains discussed above, we now know that mammalian A20 zinc fingers also possess ligase activity Mattera et al. Several bacterial virulence proteins also function as ring domain e3 ubiquitin ligases ligases in eukaryotic host cells, despite having no sequence or structural similarity to mammalian E3s Diao et al.

The potential for additional domains in mammals, as well as in other organisms, to have E3 activity cannot be discounted. Additionally, there is recent evidence that other domains within E3s, including various ubiquitin-binding domains and as-yet-uncharacterized regions, might have distinct effects on ubiquitylation.

As exemplified by the discussion of E3s in this Cell Science at ring domain e3 ubiquitin ligases Glance article, as well as other recent works Weissman et al. The systematic name of this enzyme class is ubiquitin: This enzyme is also called ubiquitin-activating enzyme.

This enzyme participates in 3 metabolic pathways: The ubiquitin ligase is referred to as an E3, and operates in conjunction with an E1 ring domain e3 ubiquitin ligases enzyme and an E2 ubiquitin-conjugating enzyme.

Ubiquitin ligase

There is one major E1 enzyme, shared by all ubiquitin ligases, that uses ATP to activate ubiquitin for conjugation and transfers it to an E2 enzyme. The E2 enzyme interacts with a specific E3 partner and transfers the ubiquitin to the target protein.


ring domain e3 ubiquitin ligases The E3, which may be a multi-protein complexis, in general, responsible for targeting ubiquitination to specific substrate proteins. In the conserved first step, an E1 cysteine residue attacks the ATP-activated C-terminal glycine on ubiquitin, resulting in a thioester Ub-S-E1 complex.

The energy from ATP and diphosphate hydrolysis drives the formation of this reactive thioester, and subsequent steps are thermoneutral.