RING finger, HC subclass, found in E3 ubiquitin-protein ligase Hakai, zinc finger protein 645 (ZNF645), and similar proteins; Hakai, also known as Casitas B-lineage lymphoma-transforming sequence-like protein 1, RING finger protein 188 (RNF188), or c-Cbl-like protein 1 (CBLL1), is an E3 ubiquitin ligase that disrupts cell-cell contacts in epithelial cells and is upregulated in human colon and gastric adenocarcinomas. It was identified to mediate the posttranslational downregulation of E-cadherin (CDH1), a major component of adherens junctions in epithelial cells and a potent tumor suppressor. It also promotes ubiquitination of several other tyrosine-phosphorylated Src substrates, including cortactin (CTTN) and DOK1. Hakai acts as a homodimer arranged in an anti-parallel configuration with a novel HYB (Hakai pTyr-binding) domain that forms a phosphotyrosine-binding pocket. Each monomer contains a C3HC4-type RING-HC finger and a short pTyr-B domain that incorporates a novel, atypical C2H2-type Zn-finger coordination motif. Both domains are important for dimerization. ZNF645 is a novel testis-specific E3 ubiquitin-protein ligase that plays a role in sperm production and quality control. It has a structure similar to that of the c-Cbl-like protein Hakai. In contrast to Hakai, its HYB domain demonstrates different target specificities. It interacts with v-Src-phosphorylated E-cadherin, but not to cortactin.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 568977433 115 HFCDKCGLPIKVYGRMIPCKHVFCYDCAILHekkgDKMCPGCSDPVQRIEQCTRG 169
Cdd:cd16508    1 HFCDKCDLPIKIYGRMIPCKHVFCLDCARLH----DKICPRCDDPVQRIEQCTRG 51

RING finger, HC subclass, found in E3 ubiquitin-protein ligase Hakai, zinc finger protein 645 (ZNF645), and similar proteins; Hakai, also known as Casitas B-lineage lymphoma-transforming sequence-like protein 1, RING finger protein 188 (RNF188), or c-Cbl-like protein 1 (CBLL1), is an E3 ubiquitin ligase that disrupts cell-cell contacts in epithelial cells and is upregulated in human colon and gastric adenocarcinomas. It was identified to mediate the posttranslational downregulation of E-cadherin (CDH1), a major component of adherens junctions in epithelial cells and a potent tumor suppressor. It also promotes ubiquitination of several other tyrosine-phosphorylated Src substrates, including cortactin (CTTN) and DOK1. Hakai acts as a homodimer arranged in an anti-parallel configuration with a novel HYB (Hakai pTyr-binding) domain that forms a phosphotyrosine-binding pocket. Each monomer contains a C3HC4-type RING-HC finger and a short pTyr-B domain that incorporates a novel, atypical C2H2-type Zn-finger coordination motif. Both domains are important for dimerization. ZNF645 is a novel testis-specific E3 ubiquitin-protein ligase that plays a role in sperm production and quality control. It has a structure similar to that of the c-Cbl-like protein Hakai. In contrast to Hakai, its HYB domain demonstrates different target specificities. It interacts with v-Src-phosphorylated E-cadherin, but not to cortactin.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 568977433 115 HFCDKCGLPIKVYGRMIPCKHVFCYDCAILHekkgDKMCPGCSDPVQRIEQCTRG 169
Cdd:cd16508    1 HFCDKCDLPIKIYGRMIPCKHVFCLDCARLH----DKICPRCDDPVQRIEQCTRG 51

Zinc finger, C3HC4 type (RING finger); The C3HC4 type zinc-finger (RING finger) is a cysteine-rich domain of 40 to 60 residues that coordinates two zinc ions, and has the consensus sequence: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C where X is any amino acid. Many proteins containing a RING finger play a key role in the ubiquitination pathway.

                          10        20        30
                  ....*....|....*....|....*....|....*..
gi 568977433  120 CGLPIKVYGRMIPCKHVFCYDCAILHEKKGDKMCPGC 156
Cdd:pfam00097   4 CLEEPKDPVTLLPCGHLFCSKCIRSWLESGNVTCPLC 40

RING finger, HC subclass, found in E3 ubiquitin-protein ligase Hakai, zinc finger protein 645 (ZNF645), and similar proteins; Hakai, also known as Casitas B-lineage lymphoma-transforming sequence-like protein 1, RING finger protein 188 (RNF188), or c-Cbl-like protein 1 (CBLL1), is an E3 ubiquitin ligase that disrupts cell-cell contacts in epithelial cells and is upregulated in human colon and gastric adenocarcinomas. It was identified to mediate the posttranslational downregulation of E-cadherin (CDH1), a major component of adherens junctions in epithelial cells and a potent tumor suppressor. It also promotes ubiquitination of several other tyrosine-phosphorylated Src substrates, including cortactin (CTTN) and DOK1. Hakai acts as a homodimer arranged in an anti-parallel configuration with a novel HYB (Hakai pTyr-binding) domain that forms a phosphotyrosine-binding pocket. Each monomer contains a C3HC4-type RING-HC finger and a short pTyr-B domain that incorporates a novel, atypical C2H2-type Zn-finger coordination motif. Both domains are important for dimerization. ZNF645 is a novel testis-specific E3 ubiquitin-protein ligase that plays a role in sperm production and quality control. It has a structure similar to that of the c-Cbl-like protein Hakai. In contrast to Hakai, its HYB domain demonstrates different target specificities. It interacts with v-Src-phosphorylated E-cadherin, but not to cortactin.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 568977433 115 HFCDKCGLPIKVYGRMIPCKHVFCYDCAILHekkgDKMCPGCSDPVQRIEQCTRG 169
Cdd:cd16508    1 HFCDKCDLPIKIYGRMIPCKHVFCLDCARLH----DKICPRCDDPVQRIEQCTRG 51

HC subclass of RING (RING-HC) finger and its variants; The RING finger is a specialized type of Zn-finger of 40 to 60 residues that binds two atoms of zinc. It is defined by the "cross-brace" motif that chelates zinc atoms by eight amino acid residues, typically Cys or His, arranged in a characteristic spacing. Canonical RING motifs have been categorized into two major subclasses, RING-HC (C3HC4-type) and RING-H2 (C3H2C3-type), according to their Cys/His content. There are also many variants of RING fingers. Some have a different Cys/His pattern. Some lack a single Cys or His residue at typical Zn ligand positions, especially, the fourth or eighth zinc ligand is prevalently exchanged for an Asp, which can chelate Zn in a RING finger as well. This family corresponds to the HC subclass of RING (RING-HC) fingers that are characterized by containing C3HC4-type canonical RING-HC fingers or noncanonical RING-HC finger variants, including C4C4-, C3HC3D-, C2H2C4-, and C3HC5-type modified RING-HC fingers. The canonical RING-HC finger has been defined as C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C. It binds two Zn ions in a unique "cross-brace" arrangement, which distinguishes it from tandem zinc fingers and other similar motifs. RING-HC fingers can be found in a group of diverse proteins with a variety of cellular functions, including oncogenesis, development, viral replication, signal transduction, the cell cycle, and apoptosis. Many of them are ubiquitin-protein ligases (E3s) that serve as scaffolds for binding to ubiquitin-conjugating enzymes (E2s, also referred to as ubiquitin carrier proteins or UBCs) in close proximity to substrate proteins, which enables efficient transfer of ubiquitin from E2 to the substrates.

                         10        20
                 ....*....|....*....|....*...
gi 568977433 129 RMIPCKHVFCYDCAILHEKKGDKMCPGC 156
Cdd:cd16449   14 VLLPCGHVFCRECIRRLLESGSIKCPIC 41

RING finger, HC subclass, found in RING finger protein 10 (RNF10) and similar proteins; RNF10 is an E3 ubiquitin-protein ligase that interacts with mesenchyme Homeobox 2 (MEOX2) transcription factor, a regulator of the proliferation, differentiation and migration of vascular smooth muscle cells and cardiomyocytes; it enhances Meox2 activation of the p21 promoter. It also regulates the expression of myelin-associated glycoprotein (MAG) genes and is required for myelin production in Schwann cells of the peripheral nervous system. Moreover, RNF10 regulates retinoic acid-induced neuronal differentiation and the cell cycle exit of P19 embryonic carcinoma cells. RNF10 contains a C3HC4-type RING-HC finger and three putative nuclear localization signals.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|
gi 568977433 129 RMIPCKHVFCYDCaILH----EKKGDKMCPGCSDPVQRIE 164
Cdd:cd16536   14 RITRCGHIFCWPC-ILRylslSEKKWRKCPICFESIHKKD 52

Ring finger; E3 ubiquitin-protein ligase activity is intrinsic to the RING domain of c-Cbl and is likely to be a general function of this domain; Various RING fingers exhibit binding activity towards E2 ubiquitin-conjugating enzymes (Ubc' s)

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|
gi 568977433   117 CDKCGLPIKVYGRMIPCKHVFCYDCAILHEKKGDKMCPGC 156
Cdd:smart00184   1 CPICLEEYLKDPVILPCGHTFCRSCIRKWLESGNNTCPIC 40