Uncharacterized conserved protein, contains RING Zn-finger [General function prediction only];

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1475928814   59 SLVDSDFRMVLRKLSKKDVTTKLKAMQEFGTMC--TERDTETvkgVLPYWPRIFCKISLDHDRRVREATQQAFEKLILKV 136
Cdd:COG5219     40 SGLDAEMIVIVKNLQKRDIVTKCRALQDLIQWNdpSQFDNEQ---FLNALAVLFPRLSIEVEMNPRLEGLQFDSRLYEIL 116

                           90       100       110       120       130       140       150       160
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1475928814  137 KKQLAPYLKSLMGYWLMAQCDTYTPAAFAAKDAFEAAFPPSKQPEAIAFCKDEITSVLQDHLIKETPDTLSDPQTVPEEE 216
Cdd:COG5219    117 SKKIGKRLKKTILRGLLGLKDVDDTVSVEANIDTLLEIVEDKWPTIWKSFNLQIKNLVIDVLYHELLSSVEDRRKFSKEE 196

                          170       180       190       200
                   ....*....|....*....|....*....|....*....|....*.
gi 1475928814  217 REAKFYRVVTCSLLALKRLLCLLPDNELDSlEEKFKSLLSQNKFWK 262
Cdd:COG5219    197 SEWLYGRVENSEYLVLRKLFAEFVDIGLET-DKKIEKQTLEDSFVR 241

RING-CH finger, H2 subclass (C4HC3-type), found in E3 ubiquitin-protein ligase listerin and similar proteins; Listerin, also known as RING finger protein 160 or zinc finger protein 294, is the mammalian homolog of yeast Ltn1. It is widely expressed in all tissues, but motor and sensory neurons and neuronal processes in the brainstem and spinal cord are primarily affected in the mutant. Listerin is required for embryonic development and plays an important role in neurodegeneration. It also functions as a critical E3 ligase involving quality control of nonstop proteins. It mediates ubiquitylation of aberrant proteins that become stalled on ribosomes during translation. Ltn1 works with several cofactors to form a large ribosomal subunit-associated quality control complex (RQC), which mediates the ubiquitylation and extraction of ribosome-stalled nascent polypeptide chains for proteasomal degradation. It appears to first associate with nascent chain-stalled 60S subunits together with two proteins of unknown function, Tae2 and Rqc1. Listerin contains a long stretch of HEAT (Huntingtin, Elongation factor 3, PR65/A subunit of protein phosphatase 2A, and TOR) or ARM (Armadillo) repeats in the N terminus and middle region, and a catalytic RING-CH finger, also known as vRING or RINGv, with an unusual arrangement of zinc-coordinating residues in the C-terminus . Its cysteines and histidines are arranged in the sequence as C4HC3-type, rather than the C3H2C3-type in canonical RING-H2 finger.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|
gi 1475928814 1713 EDCMICFSVIHGFNYSLPKKACRTCKKKFHSACLYKWFTSSNKSTCPLCR 1762
Cdd:cd16491      1 EECPICYSVIHGSNHSLPKLKCKTCKNKFHSACLYKWFRSSNKSTCPLCR 50

Ring finger domain;

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|
gi 1475928814 1714 DCMICFSvihgfNYSLPKKACRT-CKKKFHSACLYKWFTSSNksTCPLCR 1762
Cdd:pfam13639    2 ECPICLE-----EFEEGDKVVVLpCGHHFHRECLDKWLRSSN--TCPLCR 44

RING-CH finger, H2 subclass (C4HC3-type), found in E3 ubiquitin-protein ligase listerin and similar proteins; Listerin, also known as RING finger protein 160 or zinc finger protein 294, is the mammalian homolog of yeast Ltn1. It is widely expressed in all tissues, but motor and sensory neurons and neuronal processes in the brainstem and spinal cord are primarily affected in the mutant. Listerin is required for embryonic development and plays an important role in neurodegeneration. It also functions as a critical E3 ligase involving quality control of nonstop proteins. It mediates ubiquitylation of aberrant proteins that become stalled on ribosomes during translation. Ltn1 works with several cofactors to form a large ribosomal subunit-associated quality control complex (RQC), which mediates the ubiquitylation and extraction of ribosome-stalled nascent polypeptide chains for proteasomal degradation. It appears to first associate with nascent chain-stalled 60S subunits together with two proteins of unknown function, Tae2 and Rqc1. Listerin contains a long stretch of HEAT (Huntingtin, Elongation factor 3, PR65/A subunit of protein phosphatase 2A, and TOR) or ARM (Armadillo) repeats in the N terminus and middle region, and a catalytic RING-CH finger, also known as vRING or RINGv, with an unusual arrangement of zinc-coordinating residues in the C-terminus . Its cysteines and histidines are arranged in the sequence as C4HC3-type, rather than the C3H2C3-type in canonical RING-H2 finger.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|
gi 1475928814 1713 EDCMICFSVIHGFNYSLPKKACRTCKKKFHSACLYKWFTSSNKSTCPLCR 1762
Cdd:cd16491      1 EECPICYSVIHGSNHSLPKLKCKTCKNKFHSACLYKWFRSSNKSTCPLCR 50

H2 subclass of RING (RING-H2) fingers 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 different Cys/His patterns while some lack a single Cys or His residue at typical Zn ligand positions (the fourth or eighth zinc ligand is prevalently exchanged for an Asp, which can indeed chelate Zn in a RING finger as well). This family corresponds to the H2 subclass of RING (RING-H2) finger proteins that are characterized by containing C3H2C3-type canonical RING-H2 fingers or noncanonical RING-H2 finger variants, including C4HC3- (RING-CH alias RINGv), C3H3C2-, C3H2C2D-, C3DHC3-, and C4HC2H-type modified RING-H2 fingers. The canonical RING-H2 finger has been defined as C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-H-X2-C-X(4-48)-C-X2-C, X is any amino acid and the number of X residues varies in different fingers. It binds two Zn ions in a unique "cross-brace" arrangement, which distinguishes it from tandem zinc fingers and other similar motifs. RING-H2 finger 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 serves as a scaffold 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        30        40
                   ....*....|....*....|....*....|....*....|....*...
gi 1475928814 1715 CMICFSVIHGFNyslpKKACRTCKKKFHSACLYKWFTSSNKsTCPLCR 1762
Cdd:cd16448      1 CVICLEEFEEGD----VVRLLPCGHVFHLACILRWLESGNN-TCPLCR 43

RING-CH finger, H2 subclass (C4HC3-type), found in Fanconi anemia group L protein (FANCL) and similar proteins; FANCL, also known as fanconi anemia-associated polypeptide of 43 kDa (FAAP43) or PHF9, is a monomeric RING E3 ubiquitin-protein ligase that monoubiquitinates FANCD2 and FANCI. The monoubiquitinated FANCD2-FANCI heterodimer complex in turn recruits key proteins involved in homologous recombination and DNA repair. FANCL is also one of seven components in Fanconi anemia (FA) nuclear core complex, which provides the essential E3 ligase function for spatially defined FANCD2 ubiquitination and FA pathway activation. In the FA core complex, FANCL associates with FANCB and FAAP100 to constitute a catalytic subcomplex that functions as the monoubiquitination module. FANCL specifically interacts with the E2 ubiquitin-conjugating (UBC) enzyme Ube2T to make an E3-E2 pair, which is the catalytic center of the Fanconi Anemia (FA) pathway required for DNA interstrand crosslink repair. Moreover, FANCL has a noncanonical function to regulate the Wnt/beta-catenin signaling, a pathway involved in hematopoietic stem cell self-renewal. It functionally enhances beta-catenin activity by ubiquitinating beta-catenin, with atypical ubiquitin chains (K11 linked). FANCL contains an N-terminal E2-like fold (ELF) domain, a novel double-RWD (DRWD) domain with a clear hydrophobic core, and a C-terminal C4HC3-type RING-CH finger. The DRWD domain is required for substrate binding. The RING-CH finger, also known as vRING or RINGv, is predicted to facilitate E2 binding. It has an unusual arrangement of zinc-coordinating residues. Its cysteines and histidines are arranged in the sequence as C4HC3-type, rather than the C3H2C3-type in canonical RING-H2 finger.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|....*....
gi 1475928814 1714 DCMICFSviHGFNYSLPKKACR--TCKKKFHSACLYKWF---TSSNKS------TCPLC 1761
Cdd:cd16490      1 ECGICYA--YRLDGEVPDQVCDnaRCGQPFHQSCLYEWLrslPSTRQSfntifgECPYC 57

FANCL C-terminal domain; This domain is found at the C-terminus of the Fancl protein in humans which is the putative E3 ubiquitin ligase subunit of the FA complex (Fanconi anaemia). Eight subunits of the Fanconi anaemia gene products form a multisubunit nuclear complex which is required for mono-ubiquitination of a downstream FA protein, FANCD2.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|....*....
gi 1475928814 1714 DCMICFSviHGFNYSLPKKACRT--CKKKFHSACLYKWFTSSNKS---------TCPLC 1761
Cdd:pfam11793    4 ECGICYA--YRLGGEIPDQVCDNpkCGQPFHRACLYEWLRGLPSSrqsfnvifgECPYC 60

RING finger, H2 subclass, found in rice E3 ubiquitin-protein ligase EL5 and similar proteins; EL5, also known as protein ELICITOR 5, is an E3 ubiquitin-protein ligase containing an N-terminal transmembrane domain and a C3H2C3-type RING-H2 finger that is a binding site for ubiquitin-conjugating enzyme (E2). It can be rapidly induced by N-acetylchitooligosaccharide elicitor. EL5 catalyzes polyubiquitination via the Lys48 residue of ubiquitin, and thus plays a crucial role as a membrane-anchored E3 in the maintenance of cell viability after the initiation of root primordial formation in rice. It also acts as an anti-cell death enzyme that might be responsible for mediating the degradation of cytotoxic proteins produced in root cells after the actions of phytohormones. Moreover, EL5 interacts with UBC5b, a rice ubiquitin carrier protein, through its RING-H2 finger. EL5 is an unstable protein, and its degradation is regulated by the C3H2C3-type RING-H2 finger in a proteasome-independent manner.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|.
gi 1475928814 1714 DCMICFSvihgfNYSLPKKACR--TCKKKFHSACLYKWFTSSNksTCPLCR 1762
Cdd:cd16461      1 ECAICLS-----DYENGEELRRlpECKHAFHKECIDEWLKSNS--TCPLCR 44

RING finger, H2 subclass, found in the PA-TM-RING ubiquitin ligase family; The PA-TM-RING family represents a group of transmembrane-type E3 ubiquitin ligases, which has been characterized by an N-terminal transient signal peptide, a PA (protease-associated) domain, a TM (transmembrane) domain, as well as a C-terminal C3H2C3-type RING-H2 finger domain. It includes RNF13, RNF167, ZNRF4 (zinc and RING finger 4), GRAIL (gene related to anergy in lymphocytes)/RNF128, RNF130, RNF133, RNF148, RNF149 and RNF150 (which are more closely related), as well as RNF43 and ZNRF3, which have substantially longer C-terminal tail extensions compared with the others. PA-TM-RING proteins are expressed at low levels in all mammalian tissues and species, but they are not present in yeast. They play a common regulatory role in intracellular trafficking/sorting, suggesting that abrogation of their function may result in dysregulation of cellular signaling events in cancer.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|
gi 1475928814 1714 DCMICFSvihgfNYSLPKKACR-TCKKKFHSACLYKWFTssNKSTCPLCR 1762
Cdd:cd16454      1 TCAICLE-----EFKEGEKVRVlPCNHLFHKDCIDPWLE--QHNTCPLCR 43

Anaphase-promoting complex subunit 11 RING-H2 finger; Apc11 is one of the subunits of the anaphase-promoting complex or cyclosome. The APC subunits are cullin family proteins with ubiquitin ligase activity. Polyubiquitination marks proteins for degradation by the 26S proteasome and is carried out by a cascade of enzymes that includes ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s), and ubiquitin ligases (E3s). Apc11 acts as an E3 enzyme and is responsible for recruiting E2s to the APC and for mediating the subsequent transfer of ubiquitin to APC substrates in vivo. In Saccharomyces cerevisiae this RING-H2 finger protein defines the minimal ubiquitin ligase activity of the APC, and the integrity of the RING-H2 finger is essential for budding yeast cell viability.

                           10        20        30
                   ....*....|....*....|....*....|
gi 1475928814 1737 CKKKFHSACLYKWF-TSSNKSTCPLCRETF 1765
Cdd:pfam12861   52 CSHNFHMHCILKWLhTETSKGLCPMCRQTF 81

second RING finger, H2 subclass, found in RING finger protein 32 (RNF32) and similar proteins; RNF32 is mainly expressed in testis spermatogenesis, most likely in spermatocytes and/or in spermatids, suggesting a possible role in sperm formation. RNF32 contains two C3H2C3-type RING-H2 fingers separated by an IQ domain of unknown function. Although the biological function of RNF32 remains unclear, proteins with double RING-H2 fingers may act as scaffolds for binding several proteins that function in the same pathway. This model corresponds to the second RING-H2 finger.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|....*...
gi 1475928814 1714 DCMICFSVIHGFNYSLPKKACRT-------CKKKFHSACL--YKWFTSSNKSTCPLCR 1762
Cdd:cd16678      1 DCPICLTPLQSSGDSSDAKRVSSrptvllsCSHVFHATCLeaFEEFSVGEELVCPVCR 58

RING finger, HC subclass, found in topoisomerase I-binding arginine/serine-rich protein (Topors) and similar proteins; Topors, also known as topoisomerase I-binding RING finger protein, tumor suppressor p53- binding protein 3, or p53-binding protein 3 (p53BP3), is a ubiquitously expressed nuclear E3 ubiquitin-protein ligase that can ligate both ubiquitin and small ubiquitin-like modifier (SUMO) to substrate proteins in the nucleus. It contains an N-terminal C3HC4-type RING-HC finger which ligates ubiquitin to its target proteins including DNA topoisomerase I, p53, NKX3.1, H2AX, and the AAV-2 Rep78/68 proteins. As a RING-dependent E3 ubiquitin ligase, Topors works with the E2 enzymes UbcH5a, UbcH5c, and UbcH6, but not with UbcH7, CDC34, or UbcH2b. Topors acts as a tumor suppressor in various malignancies. It regulates p53 modification, suggesting it may be responsible for astrocyte elevated gene-1 (AEG-1, also known as metadherin, or LYRIC) ubiquitin modification. Plk1-mediated phosphorylation of Topors inhibits Topors-mediated sumoylation of p53, whereas p53 ubiquitination is enhanced, leading to p53 degradation. It also functions as a negative regulator of the prostate tumor suppressor NKX3.1. Moreover, Topors is associated with promyelocytic leukemia nuclear bodies, and may be involved in the cellular response to camptothecin. It also plays a key role in the turnover of H2AX protein, discriminating the type of DNA damaging stress. Furthermore, Topors is a cilia-centrosomal protein associated with autosomal dominant retinal degeneration. Mutations in TOPORS cause autosomal dominant retinitis pigmentosa (adRP).

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|...
gi 1475928814 1713 EDCMICFSvihgfNYSLPKKACRTCKKKFHSACLYKWftSSNKSTCPLCRETF 1765
Cdd:cd16574      2 SSCPICLD-----RFENEKAFLDGCFHAFCFTCILEW--SKVKNECPLCKQPF 47

RING finger, H2 subclass, found in Saccharomyces cerevisiae transmembrane E3 ubiquitin-protein ligase 1 (TUL1) and similar proteins; This subfamily includes Saccharomyces cerevisiae TUL1, Schizosaccharomyces pombe DSC E3 ubiquitin ligase complex subunit 1 (DSC1), and Arabidopsis thaliana protein FLYING SAUCER 2 (FLY2). TUL1 is the catalytic component of DSC E3 ubiquitin ligase complexes that tag proteins present in Golgi, endosome and vacuole membranes and function in protein homeostasis under non-stress conditions, and support a role in protein quality control. It mediates ubiquitination of vacuolar proteins such as CPS1, PPN1, PEP12 and other proteins containing exposed hydrophilic residues within their transmembrane domains, leading to their sorting into internal vesicles in late endosomes. TUL1 also targets the unpalmitoylated endosomal SNARE TLG1 to the multivesicular body (MVB) pathway. DSC1, also known as defective for SREBP cleavage protein 1, is the catalytic component of the DSC E3 ubiquitin ligase complex required for the sre1 transcriptional activator proteolytic cleavage to release the soluble transcription factor from the membrane in low oxygen or sterol conditions. FLY2 acts as an E3 ubiquitin-protein ligase that may be involved in xylem development. Members of this subfamily contain a C3H2C3-type RING-H2 finger.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|....*.
gi 1475928814 1710 EGVEDCMICFSVIHGFNYSLPKKACRT--CKKKFHSACLYKWFTSsnKSTCPLCRE 1763
Cdd:cd23117      2 NGSVDCVICMSDIELPSTNSVRRDYMVtpCNHIFHTNCLERWMDI--KLECPTCRR 55

Component of SCF ubiquitin ligase and anaphase-promoting complex [Posttranslational modification, protein turnover, chaperones / Cell division and chromosome partitioning];

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1475928814 1712 VEDCMICFSVIHGF-----NYSLPKKACR----TCKKKFHSACLYKWFTSsnKSTCPLCRETF 1765
Cdd:COG5194     20 IDVCAICRNHIMGTcpecqFGMTPGDECPvvwgVCNHAFHDHCIYRWLDT--KGVCPLDRQTW 80

RING finger, H2 subclass, found in DAZ (deleted in azoospermia)-interacting protein 3 (DZIP3) and similar proteins; DZIP3, also known as RNA-binding ubiquitin ligase of 138 kDa (RUL138) or 2A-HUB protein, is an RNA-binding E3 ubiquitin-protein ligase that interacts with coactivator-associated arginine methyltransferase 1 (CARM1) and acts as a transcriptional coactivator of estrogen receptor (ER) alpha. It is also a histone H2A ubiquitin ligase that catalyzes monoubiquitination of H2A at lysine 119, functioning as a combinatorial component of the repression machinery required for repressing a specific chemokine gene expression program, critically modulating migratory responses to Toll-like receptors (TLR) activation. DZIP3 contains a C3H2C3-type RING-H2 finger at the C-terminus.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|
gi 1475928814 1713 EDCMICFSVIHGFNYSLPkkacRTCKKKFHSACLYKWFTssNKSTCPLCR 1762
Cdd:cd16460      1 TPCVICHEAFSDGDRLLV----LPCAHKFHTQCIGPWLD--GQQTCPTCR 44

RING finger, H2 subclass, found in RING finger proteins RNF139, RNF145, and similar proteins; RNF139, also known as translocation in renal carcinoma on chromosome 8 protein (TRC8), is an endoplasmic reticulum (ER)-resident multi-transmembrane protein that functions as a potent growth suppressor in mammalian cells, inducing G2/M arrest, decreased DNA synthesis and increased apoptosis. It is a tumor suppressor that has been implicated in a novel regulatory relationship linking the cholesterol/lipid biosynthetic pathway with cellular growth control. A mutation in RNF139 has been identified in families with hereditary renal (RCC) and thyroid cancers. RNF145 is an uncharacterized RING finger protein encoded by the RNF145 gene, which is expressed in T lymphocytes, and its expression is altered in acute myelomonocytic and acute promyelocytic leukemias. Although its biological function remains unclear, RNF145 shows high sequence similarity with RNF139. Both RNF139 and RNF145 contain a C3H2C3-type RING-H2 finger with possible E3-ubiquitin ligase activity.

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|....*...
gi 1475928814 1715 CMICFSVIhgfnyslpKKACRT-CKKKFHSACLYKWFTSsnKSTCPLC 1761
Cdd:cd16476      3 CAICYQEM--------KEARITpCNHFFHGLCLRKWLYV--QDTCPLC 40

RING finger, H2 subclass, found in RING finger protein 181 (RNF181) and similar proteins; RNF181, also known as HSPC238, is a platelet E3 ubiquitin-protein ligase containing a C3H2C3-type RING-H2 finger. It interacts with the KVGFFKR motif of platelet integrin alpha(IIb)beta3, suggesting a role for RNF181-mediated ubiquitination in integrin and platelet signaling. It also suppresses the tumorigenesis of hepatocellular carcinoma (HCC) through the inhibition of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling in the liver.

                           10        20
                   ....*....|....*....|....*..
gi 1475928814 1736 TCKKKFHSACLYKWFTSSNksTCPLCR 1762
Cdd:cd16669     19 PCKHSFHSDCILPWLGKTN--SCPLCR 43

RING finger, H2 subclass, found in BRCA1-associated protein (BRAP2) and similar proteins; BRAP2, also known as impedes mitogenic signal propagation (IMP), RING finger protein 52, or renal carcinoma antigen NY-REN-63, is a novel cytoplasmic protein interacting with the two functional nuclear localization signal (NLS) motifs of BRCA1, a nuclear protein linked to breast cancer. It also binds to the SV40 large T antigen NLS motif and the bipartite NLS motif found in mitosin. BRAP2 serves as a cytoplasmic retention protein and plays a role in the regulation of nuclear protein transport. It contains an N-terminal RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), followed by a C3H2C3-type RING-H2 finger and a UBP-type zinc finger.

                           10        20
                   ....*....|....*....|....*..
gi 1475928814 1737 CKKKFHSACLYKWftssNKSTCPLCRE 1763
Cdd:cd16457     22 CNHSFHCSCLSKW----GDSSCPVCRY 44

RING-CH finger, H2 subclass (C4HC3-type), found in transcriptional repressor NF-X1, NF-X1-type zinc finger protein NFXL1, and similar proteins; NF-X1, also known as nuclear transcription factor, X box-binding protein 1, is a novel cysteine-rich sequence-specific DNA-binding protein that interacts with the conserved X-box motif of the human major histocompatibility complex (MHC) class II genes via a repeated Cys-His domain. It functions as a cytokine-inducible transcriptional repressor that plays an important role in regulating the duration of an inflammatory response by limiting the period in which class II MHC molecules are induced by interferon gamma (IFN- gamma). NFXL1, also known as NF-X1-type zinc finger protein NFXL1 or ovarian zinc finger protein (OZFP), is encoded by a novel human cytoplasm-distribution zinc finger protein (CDZFP) gene. This subfamily also includes NF-X1 homologs from insects, plants, and fungi. Drosophila melanogaster shuttle craft (STC) is a DNA- or RNA-binding protein required for proper axon guidance in the central nervous system. It functions as a putative transcription factor and plays an essential role in the completion of embryonic development. In contrast to NF-X1, STC contains an RD domain. The Arabidopsis genome encodes two NF-X1 homologs, AtNFXL1 and AtNFXL2, both of which function as regulators of salt stress responses. The AtNFXL1 protein is a nuclear factor that positively affects adaptation to salt stress. It also functions as a negative regulator of the type A trichothecene phytotoxin-induced defense response. AtNFXL2 controls abscisic acid (ABA) levels and suppresses ABA responses. It may also prevent unnecessary and costly stress adaptation under favorable conditions. FKBP12-associated protein 1 (FAP1) is a dosage suppressor of rapamycin toxicity in budding yeast. It is localized in the cytoplasm, but upon rapamycin treatment translocates to the nucleus. FAP1 interacts with FKBP12 in a rapamycin-sensitive manner. It is a proline-rich protein containing a novel cysteine-rich DNA-binding motif. Unique structural features of the NFX1 and NFXL proteins are the Cys-rich region and a specific RING-CH finger motif with an unusual arrangement of zinc-coordinating residues. The Cys-rich region is required for binding to specific promoter elements. It frequently comprises more than 500 amino acids and harbors several NFX1-type zinc finger domains, characterized by the pattern C-X(1-6)-H-X-C-X3-C(H/C)-X(3-4)-(H/C)-X(1-10)-C. The RING-CH finger, also known as vRING or RINGv, may have E3 ligase activity. It is characterized by a C4HC3-type Zn ligand signature and additional conserved amino acids, rather than the C3H2C3-type cysteines and histidines arrangement in canonical RING-H2 finger. In addition to the Cys-rich region and RING-CH finger, NFX1 contains a PAM2 motif in the N-terminus and a R3H domain in the C-terminus.

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|
gi 1475928814 1714 DCMICFSVIhgfNYSLPKKACRTCKKKFHSACLYKWFTSSNKST-----------CPLCR 1762
Cdd:cd16492      2 ECMICTENV---GRNQSIWSCSRCYRVFHLSCIKKWAKNSEEKAeqvkndddswrCPGCQ 58