SPL-RING finger found in E3 SUMO-protein ligase NSE2 and similar proteins; NSE2, also known as MMS21 homolog (MMS21) or non-structural maintenance of chromosomes element 2 homolog (Non-SMC element 2 homolog, NSMCE2), is an autosumoylating small ubiquitin-like modifier (SUMO) ligase required for the response to DNA damage. It regulates sumoylation and nuclear-to-cytoplasmic translocation of skeletal and heart muscle-specific variant of the alpha subunit of nascent polypeptide associated complex (skNAC)-Smyd1 in myogenesis. It is also required for resisting extrinsically induced genotoxic stress. Moreover, NSE2 together with its partner proteins SMC6 and SMC5 form a tight subcomplex of the structural maintenance of chromosomes SMC5-6 complex, which includes another two subcomplexes, NSE1-NSE3-NSE4 and NSE5-NSE6. SMC6 and NSE3 are sumoylated in an NSE2-dependent manner, but SMC5 and NSE1 are not. NSE2-dependent E3 SUMO ligase activity is required for efficient DNA repair, but not for SMC5-6 complex stability. NSE2 contains a RING variant known as a Siz/PIAS (protein inhibitor of activated signal transducer and activator of transcription)-like RING (SPL-RING) finger that is likely shared by the SP-RING type SUMO E3 ligases, such as PIAS family proteins. The SPL-RING finger is a variant of the RING finger, which lacks the second, fifth, and sixth zinc-binding residues of the consensus C3H2C3-/C3HC4-type RING fingers. It harbors only one Zn binding site and is required for the sumoylating activity.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1761178518 193 FICPITQLEMKKPVKNKMCGHTYEEEAIVRMIeskHKRKKKACCPKIGCSHTDmRMSDLIPDEALRRAIE 262
Cdd:cd16651     1 LKCPITQQLMVDPVRNKKCGHTYEKAAILQYL---QSRKKKAKCPVAGCRNTV-SKSDLVPDPELKRRIE 66

SPL-RING finger found in E3 SUMO-protein ligase NSE2 and similar proteins; NSE2, also known as MMS21 homolog (MMS21) or non-structural maintenance of chromosomes element 2 homolog (Non-SMC element 2 homolog, NSMCE2), is an autosumoylating small ubiquitin-like modifier (SUMO) ligase required for the response to DNA damage. It regulates sumoylation and nuclear-to-cytoplasmic translocation of skeletal and heart muscle-specific variant of the alpha subunit of nascent polypeptide associated complex (skNAC)-Smyd1 in myogenesis. It is also required for resisting extrinsically induced genotoxic stress. Moreover, NSE2 together with its partner proteins SMC6 and SMC5 form a tight subcomplex of the structural maintenance of chromosomes SMC5-6 complex, which includes another two subcomplexes, NSE1-NSE3-NSE4 and NSE5-NSE6. SMC6 and NSE3 are sumoylated in an NSE2-dependent manner, but SMC5 and NSE1 are not. NSE2-dependent E3 SUMO ligase activity is required for efficient DNA repair, but not for SMC5-6 complex stability. NSE2 contains a RING variant known as a Siz/PIAS (protein inhibitor of activated signal transducer and activator of transcription)-like RING (SPL-RING) finger that is likely shared by the SP-RING type SUMO E3 ligases, such as PIAS family proteins. The SPL-RING finger is a variant of the RING finger, which lacks the second, fifth, and sixth zinc-binding residues of the consensus C3H2C3-/C3HC4-type RING fingers. It harbors only one Zn binding site and is required for the sumoylating activity.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1761178518 193 FICPITQLEMKKPVKNKMCGHTYEEEAIVRMIeskHKRKKKACCPKIGCSHTDmRMSDLIPDEALRRAIE 262
Cdd:cd16651     1 LKCPITQQLMVDPVRNKKCGHTYEKAAILQYL---QSRKKKAKCPVAGCRNTV-SKSDLVPDPELKRRIE 66

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 1761178518  193 FICPITQLEMKKPVKNKMcGHTYEEEAIVRMIESKHKrkkkacCPKigcSHTDMRMSDLIPDEALRRAIES 263
Cdd:smart00504   2 FLCPISLEVMKDPVILPS-GQTYERSAIEKWLLSHGT------DPV---TGQPLTHEDLIPNLALKSAIQE 62

SPL-RING finger found in E3 SUMO-protein ligase NSE2 and similar proteins; NSE2, also known as MMS21 homolog (MMS21) or non-structural maintenance of chromosomes element 2 homolog (Non-SMC element 2 homolog, NSMCE2), is an autosumoylating small ubiquitin-like modifier (SUMO) ligase required for the response to DNA damage. It regulates sumoylation and nuclear-to-cytoplasmic translocation of skeletal and heart muscle-specific variant of the alpha subunit of nascent polypeptide associated complex (skNAC)-Smyd1 in myogenesis. It is also required for resisting extrinsically induced genotoxic stress. Moreover, NSE2 together with its partner proteins SMC6 and SMC5 form a tight subcomplex of the structural maintenance of chromosomes SMC5-6 complex, which includes another two subcomplexes, NSE1-NSE3-NSE4 and NSE5-NSE6. SMC6 and NSE3 are sumoylated in an NSE2-dependent manner, but SMC5 and NSE1 are not. NSE2-dependent E3 SUMO ligase activity is required for efficient DNA repair, but not for SMC5-6 complex stability. NSE2 contains a RING variant known as a Siz/PIAS (protein inhibitor of activated signal transducer and activator of transcription)-like RING (SPL-RING) finger that is likely shared by the SP-RING type SUMO E3 ligases, such as PIAS family proteins. The SPL-RING finger is a variant of the RING finger, which lacks the second, fifth, and sixth zinc-binding residues of the consensus C3H2C3-/C3HC4-type RING fingers. It harbors only one Zn binding site and is required for the sumoylating activity.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1761178518 193 FICPITQLEMKKPVKNKMCGHTYEEEAIVRMIeskHKRKKKACCPKIGCSHTDmRMSDLIPDEALRRAIE 262
Cdd:cd16651     1 LKCPITQQLMVDPVRNKKCGHTYEKAAILQYL---QSRKKKAKCPVAGCRNTV-SKSDLVPDPELKRRIE 66

SP-RING finger and SPL-RING finger, variants of RING fingers; This family corresponds to a group of proteins with variants of RING fingers that are characterized by lacking the second, fifth, and sixth Zn2+ ion-coordinating residues compared with the classic C3H2C3-/C3HC4-type RING fingers. They include SP-RING finger found in the Siz/PIAS RING (SP-RING) family of SUMO E3 ligases and SPL-RING finger found in E3 SUMO-protein ligase NSE2. The SP-RING family includes PIAS (protein inhibitor of activated STAT) proteins, Zmiz proteins, and Siz proteins from plants and fungi. The PIAS (protein inhibitor of activated STAT) protein family modulates the activity of several transcription factors and acts as an E3 ubiquitin ligase in the sumoylation pathway. NSE2, also known as MMS21 homolog (MMS21) or non-structural maintenance of chromosomes element 2 homolog (Non-SMC element 2 homolog, NSMCE2), is an autosumoylating small ubiquitin-like modifier (SUMO) ligase required for the response to DNA damage. It regulates sumoylation and nuclear-to-cytoplasmic translocation of skeletal and heart muscle-specific variant of the alpha subunit of nascent polypeptide associated complex (skNAC)-Smyd1 in myogenesis. It is also required for resisting extrinsically induced genotoxic stress.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 1761178518 193 FICPITQLEMKKPVKNKMCGHTYEEEAIVRMIESKHKRKKkacCP 237
Cdd:cd16452     1 LKCPITQKRMKDPVRGKHCGHCFDLEAILQYLKRRKKKWK---CP 42

U-box domain, a modified RING finger, found in WD repeat, SAM and U-box domain-containing protein 1 (WDSUB1) and similar proteins; WDSUB1 is an uncharacterized protein containing seven WD40 repeats and a SAM domain in addition to the U-box. Its biological role remains unclear. This subfamily also includes many uncharacterized kinase domain-containing U-box (AtPUB) proteins and several MIF4G motif-containing AtPUB proteins from Arabidopsis.

                          10        20        30
                  ....*....|....*....|....*....|....*...
gi 1761178518 193 FICPITQLEMKKPVknkMC--GHTYEEEAIVRMIESKH 228
Cdd:cd16655     4 FLCPITQELMRDPV---VAadGHTYERSAIEEWLETHN 38

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.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1761178518 193 FICPITQLEMKKPVKNKMcGHTYEEEAIVRMIESKHKRkkkacCPK 238
Cdd:cd16664     4 FICPISLELMKDPVILAT-GQTYERAAIEKWLDSGNNT-----CPI 43

RING-type zinc-finger; This zinc-finger is a typical RING-type of plant ubiquitin ligases.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 1761178518 195 CPITQLEMKKPVKNkmCGHTYEEEAIVRMiesKHKRKKKACCP 237
Cdd:pfam13445   1 CPICLELFTDPVLP--CGHTFCRECLEEM---SQKKGGKFKCP 38

first U-box domain, a modified RING finger, found in Legionella pneumophila U-box protein LubX and similar proteins; LubX, also called RING-type E3 ubiquitin transferase LubX, is part of the large arsenal of effectors in Legionella pneumophila that are translocated into the host cytosol during infection. LubX acts as an E3 ubiquitin-protein ligase (EC 2.3.2.27) that interferes with the host's ubiquitination pathway. LubX contains two RING-like U-box domains. U-box 1 is critical to the ubiquitin ligase activity, and U-box 2 mediates interaction with host target. This model corresponds to the first one.

                          10        20        30
                  ....*....|....*....|....*....|....*
gi 1761178518 193 FICPITQLEMKKPVKNKMcGHTYEEEAIVRMIESK 227
Cdd:cd23149     1 FTCPITSGFMEDPVITPS-GFSYERSAIERWLETK 34

RING-like Rtf2 domain, C2HC2-type, found in the replication termination factor 2 (Rtf2) protein family; The Rtf2 protein family includes a group of conserved proteins found in eukaryotes ranging from fission yeast to humans. The defining member of the family is Schizosaccharomyces pombe Rtf2 (SpRtf2), which is a proliferating cell nuclear antigen-interacting protein that functions as a key requirement for efficient replication termination at the site-specific replication barrier RTS1. It promotes termination at RTS1 by preventing replication restart. SpRtf2 contains a RING-like Rtf2 domain that is characterized by a C2HC2 motif similar to C3HC4 RING-HC finger motif known to bind two Zn2+ ions and mediate protein-protein interactions. The C2HC2 motif lacks three of the seven conserved cysteines of the C3HC4 motif, and forms only one functional Zn2+ ion-binding site. The RING-like Rtf2 domain in fission yeast is required to stabilize a paused DNA replication fork during imprinting at the mating type locus, possibly by facilitating sumoylation of PCNA. The family also includes Arabidopsis RTF2 (AtRTF2), an essential nuclear protein required for both normal embryo development and for proper expression of the GFP reporter gene. It plays a critical role in splicing the GFP pre-mRNA, and may also have a more transient regulatory role during the spliceosome cycle. The biological function of Rtf2 homologs found in eumetazoa remains unclear. They contain a variant C2HC2 motif where the middle conserved histidine has been replaced by cysteine.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1761178518 193 FICPITQLEMK---KPVKNKMCGHTYEEEAIvRMIeskhkrKKKACCPKigCS 242
Cdd:cd16653     1 FICPITGLEMNgkyKFVYLWPCGCVFSERAL-KEL------KGSKKCPV--CG 44