U-box domain, a modified RING finger, found in RING finger protein 37 (RNF37); RNF37, also known as KIAA0860, U-box domain-containing protein 5 (UBOX5), UbcM4-interacting protein 5 (UIP5), or ubiquitin-conjugating enzyme 7-interacting protein 5, is an E3 ubiquitin-protein ligase found exclusively in the nucleus as part of a nuclear dot-like structure. It interacts with the molecular chaperone VCP/p97 protein. RNF37 contains a U-box domain followed by a potential nuclear location signal (NLS), and a C-terminal C3HC4-type RING-HC finger. The U-box domain is a modified RING finger domain that lacks the hallmark metal-chelating cysteines and histidines of the latter, but is likely to adopt a RING finger-like conformation. The presence of the U-box, but not of the RING finger, is required for the E3 activity. The U-box domain can directly interact with several E2 enzymes, including UbcM2, UbcM3, UbcM4, UbcH5, and UbcH8, suggesting a similar function as the RING finger in the ubiquitination pathway. This model corresponds to the U-box domain.

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                 ....*....|....*....|....*....|....*....|....*....|...
gi 389886556 260 PEEFLDPITLEIMPCPMLLPSGKVIDQSTLEKCNRSEATWGRVPSDPFTGVAF 312
Cdd:cd16660    1 PEEFLDPITCELMTLPVLLPSGKVVDQSTLEKYIKEEATWGRLPSDPFTGVPF 53

U-box domain, a modified RING finger, found in RING finger protein 37 (RNF37); RNF37, also known as KIAA0860, U-box domain-containing protein 5 (UBOX5), UbcM4-interacting protein 5 (UIP5), or ubiquitin-conjugating enzyme 7-interacting protein 5, is an E3 ubiquitin-protein ligase found exclusively in the nucleus as part of a nuclear dot-like structure. It interacts with the molecular chaperone VCP/p97 protein. RNF37 contains a U-box domain followed by a potential nuclear location signal (NLS), and a C-terminal C3HC4-type RING-HC finger. The U-box domain is a modified RING finger domain that lacks the hallmark metal-chelating cysteines and histidines of the latter, but is likely to adopt a RING finger-like conformation. The presence of the U-box, but not of the RING finger, is required for the E3 activity. The U-box domain can directly interact with several E2 enzymes, including UbcM2, UbcM3, UbcM4, UbcH5, and UbcH8, suggesting a similar function as the RING finger in the ubiquitination pathway. This model corresponds to the U-box domain.

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                 ....*....|....*....|....*....|....*....|....*....|...
gi 389886556 260 PEEFLDPITLEIMPCPMLLPSGKVIDQSTLEKCNRSEATWGRVPSDPFTGVAF 312
Cdd:cd16660    1 PEEFLDPITCELMTLPVLLPSGKVVDQSTLEKYIKEEATWGRLPSDPFTGVPF 53

Modified RING finger domain; Modified RING finger domain, without the full complement of Zn2+-binding ligands. Probable involvement in E2-dependent ubiquitination.

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                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 389886556   262 EFLDPITLEIMPCPMLLPSGKVIDQSTLEKCNRSeatwgrVPSDPFTGVAFTpHSQPLPHPSLKARIDHF 331
Cdd:smart00504   1 EFLCPISLEVMKDPVILPSGQTYERSAIEKWLLS------HGTDPVTGQPLT-HEDLIPNLALKSAIQEW 63

U-box domain, a modified RING finger, found in RING finger protein 37 (RNF37); RNF37, also known as KIAA0860, U-box domain-containing protein 5 (UBOX5), UbcM4-interacting protein 5 (UIP5), or ubiquitin-conjugating enzyme 7-interacting protein 5, is an E3 ubiquitin-protein ligase found exclusively in the nucleus as part of a nuclear dot-like structure. It interacts with the molecular chaperone VCP/p97 protein. RNF37 contains a U-box domain followed by a potential nuclear location signal (NLS), and a C-terminal C3HC4-type RING-HC finger. The U-box domain is a modified RING finger domain that lacks the hallmark metal-chelating cysteines and histidines of the latter, but is likely to adopt a RING finger-like conformation. The presence of the U-box, but not of the RING finger, is required for the E3 activity. The U-box domain can directly interact with several E2 enzymes, including UbcM2, UbcM3, UbcM4, UbcH5, and UbcH8, suggesting a similar function as the RING finger in the ubiquitination pathway. This model corresponds to the U-box domain.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 389886556 260 PEEFLDPITLEIMPCPMLLPSGKVIDQSTLEKCNRSEATWGRVPSDPFTGVAF 312
Cdd:cd16660    1 PEEFLDPITCELMTLPVLLPSGKVVDQSTLEKYIKEEATWGRLPSDPFTGVPF 53

Modified RING finger domain; Modified RING finger domain, without the full complement of Zn2+-binding ligands. Probable involvement in E2-dependent ubiquitination.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 389886556   262 EFLDPITLEIMPCPMLLPSGKVIDQSTLEKCNRSeatwgrVPSDPFTGVAFTpHSQPLPHPSLKARIDHF 331
Cdd:smart00504   1 EFLCPISLEVMKDPVILPSGQTYERSAIEKWLLS------HGTDPVTGQPLT-HEDLIPNLALKSAIQEW 63

U-box domain, a modified RING finger; The U-box protein family is a family of E3 enzymes that also includes the HECT family and the RING finger family. The E3 enzyme is ubiquitin-protein ligase that cooperates with a ubiquitin-activating enzyme (E1) and a ubiquitin-conjugating enzyme (E2), and plays a central role in determining the specificity of the ubiquitination system. It removes the ubiquitin molecule from the E2 enzyme and attaches it to the target substrate, forming a covalent bond between ubiquitin and the target. U-box proteins are characterized by the presence of a U-box domain of approximately 70 amino acids. The U-box is a modified form of the RING finger domain that lacks metal chelating cysteines and histidines. It resembles the cross-brace RING structure consisting of three beta-sheets and a single alpha-helix, which would be stabilized by salt bridges instead of chelated metal ions. U-box proteins are widely distributed among eukaryotic organisms and show a higher prevalence in plants than in other organisms.

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                 ....*....|....*....|....*....|....*....|....*....|
gi 389886556 263 FLDPITLEIMPCPMLLPSGKVIDQSTLEKCNRSEatwgrvPSDPFTGVAF 312
Cdd:cd16453    1 FLCPISGELMKDPVITPSGITYDRSAIERWLLSD------NTDPFTREPL 44

U-box domain, a modified RING finger, found in carboxyl terminus of HSP70-interacting protein (CHIP) and similar proteins; CHIP, also known as STIP1 homology and U box-containing protein 1 (STUB1), CLL-associated antigen KW-8, or Antigen NY-CO-7, is a multifunctional protein that functions both as a co-chaperone and an E3 ubiquitin-protein ligase. It couples protein folding and proteasome mediated degradation by interacting with heat shock proteins (e.g. HSC70) and ubiquitinating their misfolded client proteins, thereby targeting them for proteasomal degradation. It is also important for cellular differentiation and survival (or apoptosis), as well as susceptibility to stress. It targets a wide range of proteins, such as expanded ataxin-1, ataxin-3, huntingtin, and androgen receptor, which play roles in glucocorticoid response, tau degradation, and both p53 and cAMP signaling. CHIP contains an N-terminal tetratricopeptide repeat (TPR) domain responsible for protein-protein interaction, a highly charged middle coiled-coil (CC), and a C-terminal RING-like U-box domain acting as an ubiquitin ligase.

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                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 389886556 259 VPEEFLDPITLEIMPCPMLLPSGKVIDQSTLEKCNRSEATWgrvpsDPFTGVAFTPhSQPLPHPSLKARIDHFLLQH 335
Cdd:cd16654    1 VPDYLCCKISFELMRDPVITPSGITYERKDIEEHLQRVGHF-----DPITREPLTQ-DQLIPNLALKEAIEAFLEEN 71

U-box domain, a modified RING finger, found in Arabidopsis plant U-box proteins (AtPUB) and similar proteins; The plant PUB proteins, also known as U-box domain-containing proteins, are much more numerous in Arabidopsis which has 62 in comparison with the typical 6 in most animals. The majority of AtPUBs in this subfamily are known as ARM domain-containing PUB proteins, containing a C-terminally-located, tandem ARM (armadillo) repeat protein-interaction region in addition to the U-box domain. They have been implicated in the regulation of cell death and defense. They also play important roles in other plant-specific pathways, such as controlling both self-incompatibility and pseudo-self-incompatibility, as well as acting in abiotic stress. A subgroup of ARM domain-containing PUB proteins harbors a plant-specific U-box N-terminal domain.

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                 ....*....|....*....|....*....|..
gi 389886556 260 PEEFLDPITLEIMPCPMLLPSGKVIDQSTLEK 291
Cdd:cd16664    1 PEEFICPISLELMKDPVILATGQTYERAAIEK 32