1bt0

Structural highlights

Function

[RUB1_ARATH] Ubiquitin exists either covalently attached to another protein, or free (unanchored). When covalently bound, it is conjugated to target proteins via an isopeptide bond either as a monomer (monoubiquitin), a polymer linked via different Lys residues of the ubiquitin (polyubiquitin chains) or a linear polymer linked via the initiator Met of the ubiquitin (linear polyubiquitin chains). Polyubiquitin chains, when attached to a target protein, have different functions depending on the Lys residue of the ubiquitin that is linked: Lys-11-linked is involved in ERAD (endoplasmic reticulum-associated degradation) and in cell-cycle regulation; Lys-29-linked is involved in lysosomal degradation; Lys-33-linked is involved in kinase modification; Lys-48-linked is involved in protein degradation via the proteasome; Lys-63-linked is involved in endocytosis, and DNA-damage responses. Linear polymer chains formed via attachment by the initiator Met lead to cell signaling. Ubiquitin is usually conjugated to Lys residues of target proteins, however, in rare cases, conjugation to Cys or Ser residues has been observed. When polyubiquitin is free (unanchored-polyubiquitin), it also has distinct roles, such as in activation of protein kinases, and in signaling (By similarity).^{[1] [2]} NEDD8-like protein RUB1: Appears to function as a stable post-translational protein modifier. An AMP-RUB1 intermediate is formed by an activating enzyme, distinct from the ubiquitin activating enzyme E1, which is composed of a heterodimer AXR1/ECR1. Auxin response is mediated, at least in part, through modification of the cullin AtCUL1 by the attachment of RUB1 to 'Lys-692'.^{[3] [4]}

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

See Also

• NEDD8

References

1. ↑ Pozo JC, Timpte C, Tan S, Callis J, Estelle M. The ubiquitin-related protein RUB1 and auxin response in Arabidopsis. Science. 1998 Jun 12;280(5370):1760-3. PMID:9624055
2. ↑ del Pozo JC, Estelle M. The Arabidopsis cullin AtCUL1 is modified by the ubiquitin-related protein RUB1. Proc Natl Acad Sci U S A. 1999 Dec 21;96(26):15342-7. PMID:10611386
3. ↑ Pozo JC, Timpte C, Tan S, Callis J, Estelle M. The ubiquitin-related protein RUB1 and auxin response in Arabidopsis. Science. 1998 Jun 12;280(5370):1760-3. PMID:9624055
4. ↑ del Pozo JC, Estelle M. The Arabidopsis cullin AtCUL1 is modified by the ubiquitin-related protein RUB1. Proc Natl Acad Sci U S A. 1999 Dec 21;96(26):15342-7. PMID:10611386
5. ↑ Rao-Naik C, delaCruz W, Laplaza JM, Tan S, Callis J, Fisher AJ. The rub family of ubiquitin-like proteins. Crystal structure of Arabidopsis rub1 and expression of multiple rubs in Arabidopsis. J Biol Chem. 1998 Dec 25;273(52):34976-82. PMID:9857029