U.S. flag

An official website of the United States government

Format

Send to:

Choose Destination

Links from GEO Profiles

    • Showing Current items.

    COP1 COP1 E3 ubiquitin ligase [ Homo sapiens (human) ]

    Gene ID: 64326, updated on 3-Nov-2024

    Summary

    Official Symbol
    COP1provided by HGNC
    Official Full Name
    COP1 E3 ubiquitin ligaseprovided by HGNC
    Primary source
    HGNC:HGNC:17440
    See related
    Ensembl:ENSG00000143207 MIM:608067; AllianceGenome:HGNC:17440
    Gene type
    protein coding
    RefSeq status
    VALIDATED
    Organism
    Homo sapiens
    Lineage
    Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo
    Also known as
    FAP78; RFWD2; CFAP78; RNF200
    Summary
    Enables ubiquitin protein ligase activity. Involved in positive regulation of proteasomal ubiquitin-dependent protein catabolic process; proteasome-mediated ubiquitin-dependent protein catabolic process; and response to ionizing radiation. Part of Cul4A-RING E3 ubiquitin ligase complex. [provided by Alliance of Genome Resources, Nov 2024]
    Expression
    Ubiquitous expression in testis (RPKM 5.8), colon (RPKM 4.2) and 25 other tissues See more
    Orthologs
    NEW
    Try the new Gene table
    Try the new Transcript table

    Genomic context

    See COP1 in Genome Data Viewer
    Location:
    1q25.1-q25.2
    Exon count:
    23
    Annotation release Status Assembly Chr Location
    RS_2024_08 current GRCh38.p14 (GCF_000001405.40) 1 NC_000001.11 (175944831..176207286, complement)
    RS_2024_08 current T2T-CHM13v2.0 (GCF_009914755.1) 1 NC_060925.1 (175300159..175562553, complement)
    RS_2024_09 previous assembly GRCh37.p13 (GCF_000001405.25) 1 NC_000001.10 (175913967..176176422, complement)

    Chromosome 1 - NC_000001.11Genomic Context describing neighboring genes Neighboring gene long intergenic non-protein coding RNA 2803 Neighboring gene ReSE screen-validated silencer GRCh37_chr1:175885507-175885694 Neighboring gene ReSE screen-validated silencer GRCh37_chr1:175892848-175893023 Neighboring gene H3K27ac-H3K4me1 hESC enhancer GRCh37_chr1:175903651-175904515 Neighboring gene NANOG-H3K27ac hESC enhancer GRCh37_chr1:175905380-175906244 Neighboring gene H3K27ac hESC enhancer GRCh37_chr1:175906245-175907107 Neighboring gene ribosomal protein S29 pseudogene 5 Neighboring gene microRNA 1843 Neighboring gene small Cajal body-specific RNA 3 Neighboring gene H3K4me1 hESC enhancer GRCh37_chr1:175976701-175977202 Neighboring gene MPRA-validated peak473 silencer Neighboring gene H3K4me1 hESC enhancer GRCh37_chr1:176065569-176066068 Neighboring gene ATAC-STARR-seq lymphoblastoid silent region 1569 Neighboring gene ATAC-STARR-seq lymphoblastoid silent region 1570 Neighboring gene ATAC-STARR-seq lymphoblastoid active region 2140 Neighboring gene U7 small nuclear RNA Neighboring gene OCT4-NANOG hESC enhancer GRCh37_chr1:176193870-176194506 Neighboring gene OCT4-NANOG hESC enhancer GRCh37_chr1:176194507-176195142 Neighboring gene NANOG hESC enhancer GRCh37_chr1:176196158-176197147 Neighboring gene H3K4me1 hESC enhancer GRCh37_chr1:176198991-176199490 Neighboring gene COP1 divergent transcript Neighboring gene ribosomal protein L13 pseudogene 7

    Genomic regions, transcripts, and products

    Expression

    • Project title: HPA RNA-seq normal tissues HPA RNA-seq normal tissues
    • Description: RNA-seq was performed of tissue samples from 95 human individuals representing 27 different tissues in order to determine tissue-specificity of all protein-coding genes
    • BioProject: PRJEB4337
    • Publication: PMID 24309898
    • Analysis date: Wed Apr 4 07:08:55 2018

    Bibliography

    GeneRIFs: Gene References Into Functions

    What's a GeneRIF?

    Pathways from PubChem

    Interactions

    Products Interactant Other Gene Complex Source Pubs Description

    General gene information

    Markers

    Clone Names

    • FLJ10416, RP11-318C24.3

    Gene Ontology Provided by GOA

    Function Evidence Code Pubs
    enables metal ion binding IEA
    Inferred from Electronic Annotation
    more info
     
    enables protein binding IPI
    Inferred from Physical Interaction
    more info
    PubMed 
    enables ubiquitin protein ligase activity IBA
    Inferred from Biological aspect of Ancestor
    more info
     
    enables ubiquitin protein ligase activity IMP
    Inferred from Mutant Phenotype
    more info
    PubMed 
    enables ubiquitin-protein transferase activity TAS
    Traceable Author Statement
    more info
     
    Component Evidence Code Pubs
    part_of Cul4A-RING E3 ubiquitin ligase complex IDA
    Inferred from Direct Assay
    more info
    PubMed 
    located_in cytosol TAS
    Traceable Author Statement
    more info
     
    located_in nuclear speck IEA
    Inferred from Electronic Annotation
    more info
     
    located_in nucleoplasm TAS
    Traceable Author Statement
    more info
     

    General protein information

    Preferred Names
    E3 ubiquitin-protein ligase COP1
    Names
    E3 ubiquitin-protein ligase RFWD2
    RING finger protein 200
    RING-type E3 ubiquitin transferase RFWD2
    constitutive photomorphogenesis protein 1 homolog
    constitutive photomorphogenic protein 1
    putative ubiquitin ligase COP1
    ring finger and WD repeat domain 2, E3 ubiquitin protein ligase
    NP_001001740.1
    NP_001273573.1
    NP_071902.2
    XP_005245504.1
    XP_005245505.1
    XP_006711550.1
    XP_011508183.1
    XP_016857548.1
    XP_016857549.1
    XP_016857550.1
    XP_016857551.1
    XP_016857552.1
    XP_016857553.1
    XP_016857554.1
    XP_016857555.1
    XP_016857556.1
    XP_016857558.1
    XP_016857560.1
    XP_016857561.1
    XP_016857562.1
    XP_016857563.1
    XP_016857566.1
    XP_016857569.1
    XP_047283718.1
    XP_047283734.1
    XP_047283736.1
    XP_047283738.1
    XP_047283742.1
    XP_047283749.1
    XP_047283754.1
    XP_047283755.1
    XP_054194157.1
    XP_054194158.1
    XP_054194159.1
    XP_054194160.1
    XP_054194161.1
    XP_054194162.1
    XP_054194163.1
    XP_054194164.1
    XP_054194165.1
    XP_054194166.1
    XP_054194167.1
    XP_054194168.1
    XP_054194169.1
    XP_054194170.1
    XP_054194171.1
    XP_054194172.1
    XP_054194173.1
    XP_054194174.1
    XP_054194175.1
    XP_054194176.1
    XP_054194177.1
    XP_054194178.1
    XP_054194179.1
    XP_054194180.1
    XP_054194181.1
    XP_054194182.1
    XP_054194183.1
    XP_054194184.1

    NCBI Reference Sequences (RefSeq)

    NEW Try the new Transcript table

    RefSeqs maintained independently of Annotated Genomes

    These reference sequences exist independently of genome builds. Explain

    These reference sequences are curated independently of the genome annotation cycle, so their versions may not match the RefSeq versions in the current genome build. Identify version mismatches by comparing the version of the RefSeq in this section to the one reported in Genomic regions, transcripts, and products above.

    mRNA and Protein(s)

    1. NM_001001740.4NP_001001740.1  E3 ubiquitin-protein ligase COP1 isoform b

      See identical proteins and their annotated locations for NP_001001740.1

      Status: VALIDATED

      Description
      Transcript Variant: This variant (2) uses an alternate in-frame splice site and lacks an in-frame exon in the central coding region, compared to variant 1. The encoded isoform (b, also known as delta24) is shorter, compared to isoform a.
      Source sequence(s)
      AF527539, AL359265, AY509921, BG717002, CA450176
      Consensus CDS
      CCDS44279.1
      UniProtKB/TrEMBL
      X5DR91
      Related
      ENSP00000310943.8, ENST00000308769.12
      Conserved Domains (3) summary
      PLN00181
      Location:236707
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:449486
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    2. NM_001286644.2NP_001273573.1  E3 ubiquitin-protein ligase COP1 isoform c precursor

      Status: VALIDATED

      Description
      Transcript Variant: This variant (3) differs in its 5' UTR and initiates translation at an alternate start codon, compared to variant 1. The encoded isoform (c) has a shorter and distinct N-terminus, compared to isoform a.
      Source sequence(s)
      AF527539, AL359265, BC039723, BG717002
      UniProtKB/TrEMBL
      H0Y339
      Related
      ENSP00000356638.1, ENST00000367666.5
      Conserved Domains (2) summary
      PLN00181
      Location:22491
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:185228
      7WD40; WD40 repeat [structural motif]
    3. NM_022457.7NP_071902.2  E3 ubiquitin-protein ligase COP1 isoform a

      See identical proteins and their annotated locations for NP_071902.2

      Status: VALIDATED

      Description
      Transcript Variant: This variant (1) represents the longest transcript and encodes the longest isoform (a).
      Source sequence(s)
      AL359265, BC094728, BG717002
      Consensus CDS
      CCDS30944.1
      UniProtKB/Swiss-Prot
      E9PKI0, Q504W6, Q6H103, Q8NHY2, Q9H6L7, X5D9B4
      UniProtKB/TrEMBL
      X5DR91
      Related
      ENSP00000356641.3, ENST00000367669.8
      Conserved Domains (3) summary
      PLN00181
      Location:240731
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:473510
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins

    RefSeqs of Annotated Genomes: GCF_000001405.40-RS_2024_08

    The following sections contain reference sequences that belong to a specific genome build. Explain

    Reference GRCh38.p14 Primary Assembly

    Genomic

    1. NC_000001.11 Reference GRCh38.p14 Primary Assembly

      Range
      175944831..176207286 complement
      Download
      GenBank, FASTA, Sequence Viewer (Graphics)

    mRNA and Protein(s)

    1. XM_047427793.1XP_047283749.1  E3 ubiquitin-protein ligase COP1 isoform X20

    2. XM_047427798.1XP_047283754.1  E3 ubiquitin-protein ligase COP1 isoform X25

    3. XM_047427786.1XP_047283742.1  E3 ubiquitin-protein ligase COP1 isoform X18

    4. XM_047427782.1XP_047283738.1  E3 ubiquitin-protein ligase COP1 isoform X15

    5. XM_005245447.4XP_005245504.1  E3 ubiquitin-protein ligase COP1 isoform X13

      See identical proteins and their annotated locations for XP_005245504.1

      UniProtKB/TrEMBL
      X5DR91
      Conserved Domains (3) summary
      PLN00181
      Location:236727
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:469506
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    6. XM_047427762.1XP_047283718.1  E3 ubiquitin-protein ligase COP1 isoform X8

    7. XM_006711487.4XP_006711550.1  E3 ubiquitin-protein ligase COP1 isoform X17

      See identical proteins and their annotated locations for XP_006711550.1

      UniProtKB/TrEMBL
      X5DNY7, X5DR91
      Conserved Domains (3) summary
      PLN00181
      Location:240708
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:450487
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    8. XM_047427780.1XP_047283736.1  E3 ubiquitin-protein ligase COP1 isoform X14

    9. XM_005245448.4XP_005245505.1  E3 ubiquitin-protein ligase COP1 isoform X16

      See identical proteins and their annotated locations for XP_005245505.1

      UniProtKB/TrEMBL
      X5D7N8, X5DR91
      Conserved Domains (3) summary
      PLN00181
      Location:240711
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:453490
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    10. XM_047427778.1XP_047283734.1  E3 ubiquitin-protein ligase COP1 isoform X12

    11. XM_011509881.3XP_011508183.1  E3 ubiquitin-protein ligase COP1 isoform X7

      UniProtKB/TrEMBL
      X5DR91
      Conserved Domains (3) summary
      PLN00181
      Location:240749
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:491528
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    12. XM_017002069.3XP_016857558.1  E3 ubiquitin-protein ligase COP1 isoform X19

      UniProtKB/TrEMBL
      X5D9B8
      Conserved Domains (3) summary
      PLN00181
      Location:210563
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:281324
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132155
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    13. XM_017002074.2XP_016857563.1  E3 ubiquitin-protein ligase COP1 isoform X24

      Conserved Domains (2) summary
      PLN00181
      Location:104457
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:175218
      7WD40; WD40 repeat [structural motif]
    14. XM_017002072.2XP_016857561.1  E3 ubiquitin-protein ligase COP1 isoform X22

      Conserved Domains (2) summary
      PLN00181
      Location:6477
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:195238
      7WD40; WD40 repeat [structural motif]
    15. XM_017002067.3XP_016857556.1  E3 ubiquitin-protein ligase COP1 isoform X11

      UniProtKB/TrEMBL
      X5DR91
      Conserved Domains (3) summary
      PLN00181
      Location:236683
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:449486
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    16. XM_017002063.3XP_016857552.1  E3 ubiquitin-protein ligase COP1 isoform X5

      UniProtKB/TrEMBL
      X5DR91
      Conserved Domains (3) summary
      PLN00181
      Location:236703
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:469506
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    17. XM_017002060.3XP_016857549.1  E3 ubiquitin-protein ligase COP1 isoform X2

      UniProtKB/TrEMBL
      X5DR91
      Conserved Domains (3) summary
      PLN00181
      Location:236721
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:487524
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    18. XM_017002066.3XP_016857555.1  E3 ubiquitin-protein ligase COP1 isoform X10

      UniProtKB/TrEMBL
      X5DR91
      Conserved Domains (3) summary
      PLN00181
      Location:240684
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:450487
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    19. XM_017002064.3XP_016857553.1  E3 ubiquitin-protein ligase COP1 isoform X6

      UniProtKB/TrEMBL
      X5DR91
      Conserved Domains (3) summary
      PLN00181
      Location:240702
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:468505
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    20. XM_017002065.3XP_016857554.1  E3 ubiquitin-protein ligase COP1 isoform X9

      UniProtKB/TrEMBL
      X5DR91
      Conserved Domains (3) summary
      PLN00181
      Location:240687
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:453490
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    21. XM_017002062.3XP_016857551.1  E3 ubiquitin-protein ligase COP1 isoform X4

      UniProtKB/TrEMBL
      X5DR91
      Conserved Domains (3) summary
      PLN00181
      Location:240705
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:471508
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    22. XM_017002061.3XP_016857550.1  E3 ubiquitin-protein ligase COP1 isoform X3

      UniProtKB/TrEMBL
      X5DR91
      Conserved Domains (3) summary
      PLN00181
      Location:240707
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:473510
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    23. XM_017002059.3XP_016857548.1  E3 ubiquitin-protein ligase COP1 isoform X1

      UniProtKB/TrEMBL
      X5DR91
      Conserved Domains (3) summary
      PLN00181
      Location:240725
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:491528
      7WD40; WD40 repeat [structural motif]
      cd16504
      Location:132177
      RING-HC_COP1; RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins
    24. XM_017002073.2XP_016857562.1  E3 ubiquitin-protein ligase COP1 isoform X23

      Conserved Domains (2) summary
      PLN00181
      Location:112465
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:183226
      7WD40; WD40 repeat [structural motif]
    25. XM_017002071.2XP_016857560.1  E3 ubiquitin-protein ligase COP1 isoform X21

      Conserved Domains (2) summary
      PLN00181
      Location:22485
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:203246
      7WD40; WD40 repeat [structural motif]
    26. XM_017002080.3XP_016857569.1  E3 ubiquitin-protein ligase COP1 isoform X27

      Conserved Domains (2) summary
      PLN00181
      Location:52405
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:123166
      7WD40; WD40 repeat [structural motif]
    27. XM_047427799.1XP_047283755.1  E3 ubiquitin-protein ligase COP1 isoform X27

    28. XM_017002077.3XP_016857566.1  E3 ubiquitin-protein ligase COP1 isoform X26

      Conserved Domains (2) summary
      PLN00181
      Location:74427
      PLN00181; protein SPA1-RELATED; Provisional
      sd00039
      Location:145188
      7WD40; WD40 repeat [structural motif]

    Alternate T2T-CHM13v2.0

    Genomic

    1. NC_060925.1 Alternate T2T-CHM13v2.0

      Range
      175300159..175562553 complement
      Download
      GenBank, FASTA, Sequence Viewer (Graphics)

    mRNA and Protein(s)

    1. XM_054338201.1XP_054194176.1  E3 ubiquitin-protein ligase COP1 isoform X20

    2. XM_054338206.1XP_054194181.1  E3 ubiquitin-protein ligase COP1 isoform X25

    3. XM_054338199.1XP_054194174.1  E3 ubiquitin-protein ligase COP1 isoform X18

    4. XM_054338196.1XP_054194171.1  E3 ubiquitin-protein ligase COP1 isoform X15

    5. XM_054338194.1XP_054194169.1  E3 ubiquitin-protein ligase COP1 isoform X13

    6. XM_054338189.1XP_054194164.1  E3 ubiquitin-protein ligase COP1 isoform X8

    7. XM_054338198.1XP_054194173.1  E3 ubiquitin-protein ligase COP1 isoform X17

      UniProtKB/TrEMBL
      X5DNY7
    8. XM_054338195.1XP_054194170.1  E3 ubiquitin-protein ligase COP1 isoform X14

    9. XM_054338197.1XP_054194172.1  E3 ubiquitin-protein ligase COP1 isoform X16

      UniProtKB/TrEMBL
      X5D7N8
    10. XM_054338193.1XP_054194168.1  E3 ubiquitin-protein ligase COP1 isoform X12

    11. XM_054338188.1XP_054194163.1  E3 ubiquitin-protein ligase COP1 isoform X7

    12. XM_054338200.1XP_054194175.1  E3 ubiquitin-protein ligase COP1 isoform X19

    13. XM_054338205.1XP_054194180.1  E3 ubiquitin-protein ligase COP1 isoform X24

    14. XM_054338203.1XP_054194178.1  E3 ubiquitin-protein ligase COP1 isoform X22

    15. XM_054338192.1XP_054194167.1  E3 ubiquitin-protein ligase COP1 isoform X11

    16. XM_054338186.1XP_054194161.1  E3 ubiquitin-protein ligase COP1 isoform X5

    17. XM_054338183.1XP_054194158.1  E3 ubiquitin-protein ligase COP1 isoform X2

    18. XM_054338191.1XP_054194166.1  E3 ubiquitin-protein ligase COP1 isoform X10

    19. XM_054338187.1XP_054194162.1  E3 ubiquitin-protein ligase COP1 isoform X6

    20. XM_054338190.1XP_054194165.1  E3 ubiquitin-protein ligase COP1 isoform X9

    21. XM_054338185.1XP_054194160.1  E3 ubiquitin-protein ligase COP1 isoform X4

    22. XM_054338184.1XP_054194159.1  E3 ubiquitin-protein ligase COP1 isoform X3

    23. XM_054338182.1XP_054194157.1  E3 ubiquitin-protein ligase COP1 isoform X1

    24. XM_054338204.1XP_054194179.1  E3 ubiquitin-protein ligase COP1 isoform X23

    25. XM_054338202.1XP_054194177.1  E3 ubiquitin-protein ligase COP1 isoform X21

    26. XM_054338209.1XP_054194184.1  E3 ubiquitin-protein ligase COP1 isoform X27

    27. XM_054338208.1XP_054194183.1  E3 ubiquitin-protein ligase COP1 isoform X27

    28. XM_054338207.1XP_054194182.1  E3 ubiquitin-protein ligase COP1 isoform X26