Open Close
General Information
Symbol
Dmel\Cpn
Species
D. melanogaster
Name
Calphotin
Annotation Symbol
CG4795
Feature Type
FlyBase ID
FBgn0261714
Gene Model Status
Stock Availability
Gene Snapshot
Calphotin (Cpn) encodes a glutamic acid-rich protein with a strong negative charge and a highly hydrophobic amino acid composition. It functions as an immobile Ca[2+] buffer along the base of the photoreceptor's microvilli. It protects the photoreceptor cells from Ca[2+] overload and light induced degeneration. [Date last reviewed: 2019-03-07]
Also Known As

cap

Key Links
Genomic Location
Cytogenetic map
Sequence location
3R:12,162,887..12,166,186 [-]
Recombination map

3-52

RefSeq locus
NT_033777 REGION:12162887..12166186
Sequence
Other Genome Views
The following external sites may use different assemblies or annotations than FlyBase.
Function
GO Summary Ribbons
Gene Ontology (GO) Annotations (10 terms)
Molecular Function (1 term)
Terms Based on Experimental Evidence (1 term)
CV Term
Evidence
References
Terms Based on Predictions or Assertions (0 terms)
Biological Process (2 terms)
Terms Based on Experimental Evidence (2 terms)
CV Term
Evidence
References
inferred from mutant phenotype
inferred from direct assay
inferred from mutant phenotype
Terms Based on Predictions or Assertions (1 term)
CV Term
Evidence
References
Cellular Component (7 terms)
Terms Based on Experimental Evidence (7 terms)
CV Term
Evidence
References
inferred from direct assay
inferred from direct assay
inferred from direct assay
inferred from direct assay
inferred from direct assay
inferred from direct assay
inferred from direct assay
Terms Based on Predictions or Assertions (0 terms)
Protein Family (UniProt)
-
Protein Signatures (InterPro)
    -
    Summaries
    Protein Function (UniProtKB)
    Plays important roles in both rhabdomere development and in photoreceptor cell survival. Might function as a calcium-sequestering 'sponge' to regulate the amount of free cytoplasmic calcium. It binds 0.3 mole of Ca(2+) per mole of protein.
    (UniProt, Q02910)
    Gene Model and Products
    Number of Transcripts
    2
    Number of Unique Polypeptides
    2

    Please see the JBrowse view of Dmel\Cpn for information on other features

    To submit a correction to a gene model please use the Contact FlyBase form

    Protein Domains (via Pfam)
    Isoform displayed:
    Pfam protein domains
    InterPro name
    classification
    start
    end
    Protein Domains (via SMART)
    Isoform displayed:
    SMART protein domains
    InterPro name
    classification
    start
    end
    Comments on Gene Model

    Annotated transcripts do not represent all supported alternative splices within 5' UTR.

    Low-frequency RNA-Seq exon junction(s) not annotated.

    Gene model reviewed during 5.49

    Sequence Ontology: Class of Gene
    Transcript Data
    Annotated Transcripts
    Name
    FlyBase ID
    RefSeq ID
    Length (nt)
    Assoc. CDS (aa)
    FBtr0082547
    2787
    842
    FBtr0082548
    2853
    864
    Additional Transcript Data and Comments
    Reported size (kB)

    3.0 (northern blot)

    3 (northern blot)

    Comments
    External Data
    Crossreferences
    Polypeptide Data
    Annotated Polypeptides
    Name
    FlyBase ID
    Predicted MW (kDa)
    Length (aa)
    Theoretical pI
    RefSeq ID
    GenBank
    FBpp0082020
    82.2
    842
    3.31
    FBpp0082021
    84.6
    864
    3.32
    Polypeptides with Identical Sequences

    None of the polypeptides share 100% sequence identity.

    Additional Polypeptide Data and Comments
    Reported size (kDa)

    873 (aa); 85 (kD)

    865 (aa); 85 (kD)

    Comments
    External Data
    Subunit Structure (UniProtKB)

    Homodimer.

    (UniProt, Q02910)
    Crossreferences
    Linkouts
    Sequences Consistent with the Gene Model
    Mapped Features

    Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\Cpn using the Feature Mapper tool.

    External Data
    Crossreferences
    Eukaryotic Promoter Database - A collection of databases of experimentally validated promoters for selected model organisms.
    Linkouts
    Expression Data
    Expression Summary Ribbons
    Colored tiles in ribbon indicate that expression data has been curated by FlyBase for that anatomical location. Colorless tiles indicate that there is no curated data for that location.
    For complete stage-specific expression data, view the modENCODE Development RNA-Seq section under High-Throughput Expression below.
    Transcript Expression
    No Assay Recorded
    Stage
    Tissue/Position (including subcellular localization)
    Reference
    in situ
    Stage
    Tissue/Position (including subcellular localization)
    Reference
    Additional Descriptive Data

    In adults, Cpn expression is head-specific. In eya mutants, which lack compound eyes, no expression is observed.

    Cpn transcripts are found in photoreceptor cells and ocelli but not in photoreceptor axons or optic lobes.

    Marker for
     
    Subcellular Localization
    CV Term
    Polypeptide Expression
    No Assay Recorded
    Stage
    Tissue/Position (including subcellular localization)
    Reference
    immunolocalization
    Stage
    Tissue/Position (including subcellular localization)
    Reference
    western blot
    Stage
    Tissue/Position (including subcellular localization)
    Reference
    Additional Descriptive Data

    Cpn protein is expressed very early in photoreceptor cell development and its expression is not altered in gl eye discs. It is expressed in larvae and adults in photoreceptor cell bodies of the retina. It is also expressed along their axons as they enter the optic lobes. It is also found in ocellar photoreceptors.

    Cpn protein is detected in all photoreceptor cells and in ocelli. The staining extends along the length of the photoreceptor cells and along their axons entering the optic lobes.

    Marker for
     
    Subcellular Localization
    CV Term
    Evidence
    References
    inferred from direct assay
    inferred from direct assay
    inferred from direct assay
    inferred from direct assay
    inferred from direct assay
    inferred from direct assay
    inferred from direct assay
    Expression Deduced from Reporters
    High-Throughput Expression Data
    Associated Tools

    GBrowse - Visual display of RNA-Seq signals

    View Dmel\Cpn in GBrowse 2
    RNA-Seq by Region - Search RNA-Seq expression levels by exon or genomic region
    Reference
    See Gelbart and Emmert, 2013 for analysis details and data files for all genes.
    Developmental Proteome: Life Cycle
    Developmental Proteome: Embryogenesis
    External Data and Images
    Linkouts
    BDGP expression data - Patterns of gene expression in Drosophila embryogenesis
    Fly-FISH - A database of Drosophila embryo and larvae mRNA localization patterns
    Images
    Alleles, Insertions, and Transgenic Constructs
    Classical and Insertion Alleles ( 10 )
    For All Classical and Insertion Alleles Show
     
    Other relevant insertions
    Transgenic Constructs ( 7 )
    For All Alleles Carried on Transgenic Constructs Show
    Transgenic constructs containing/affecting coding region of Cpn
    Transgenic constructs containing regulatory region of Cpn
    Deletions and Duplications ( 7 )
    Phenotypes
    Orthologs
    Human Orthologs (via DIOPT v8.0)
    Homo sapiens (Human) (20)
    Species\Gene Symbol
    Score
    Best Score
    Best Reverse Score
    Alignment
    Complementation?
    Transgene?
    1 of 15
    Yes
    No
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    Model Organism Orthologs (via DIOPT v8.0)
    Mus musculus (laboratory mouse) (20)
    Species\Gene Symbol
    Score
    Best Score
    Best Reverse Score
    Alignment
    Complementation?
    Transgene?
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    Rattus norvegicus (Norway rat) (17)
    1 of 13
    Yes
    No
    1 of 13
    Yes
    Yes
    1 of 13
    Yes
    No
    1 of 13
    Yes
    No
    1 of 13
    Yes
    No
    1 of 13
    Yes
    Yes
    1 of 13
    Yes
    No
    1 of 13
    Yes
    Yes
    1 of 13
    Yes
    No
    1 of 13
    Yes
    Yes
    1 of 13
    Yes
    No
    1 of 13
    Yes
    No
    1 of 13
    Yes
    No
    1 of 13
    Yes
    No
    1 of 13
    Yes
    No
    1 of 13
    Yes
    Yes
    1 of 13
    Yes
    No
    Xenopus tropicalis (Western clawed frog) (15)
    1 of 12
    Yes
    No
    1 of 12
    Yes
    Yes
    1 of 12
    Yes
    No
    1 of 12
    Yes
    No
    1 of 12
    Yes
    No
    1 of 12
    Yes
    No
    1 of 12
    Yes
    No
    1 of 12
    Yes
    No
    1 of 12
    Yes
    No
    1 of 12
    Yes
    Yes
    1 of 12
    Yes
    No
    1 of 12
    Yes
    No
    1 of 12
    Yes
    Yes
    1 of 12
    Yes
    No
    1 of 12
    Yes
    No
    Danio rerio (Zebrafish) (17)
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    Caenorhabditis elegans (Nematode, roundworm) (21)
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    No
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    No
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    No
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    No
    1 of 15
    Yes
    Yes
    1 of 15
    Yes
    Yes
    Arabidopsis thaliana (thale-cress) (0)
    No records found.
    Saccharomyces cerevisiae (Brewer's yeast) (2)
    1 of 15
    Yes
    No
    1 of 15
    Yes
    No
    Schizosaccharomyces pombe (Fission yeast) (0)
    No records found.
    Ortholog(s) in Drosophila Species (via OrthoDB v9.1) ( EOG09190HBV )
    Organism
    Common Name
    Gene
    AAA Syntenic Ortholog
    Multiple Dmel Genes in this Orthologous Group
    Drosophila simulans
    Drosophila sechellia
    Drosophila erecta
    Drosophila yakuba
    Drosophila ananassae
    Drosophila pseudoobscura pseudoobscura
    Drosophila willistoni
    Drosophila willistoni
    Drosophila virilis
    Drosophila mojavensis
    Drosophila grimshawi
    Orthologs in non-Drosophila Dipterans (via OrthoDB v9.1) ( None identified )
    No non-Drosophilid orthologies identified
    Orthologs in non-Dipteran Insects (via OrthoDB v9.1) ( None identified )
    No non-Dipteran orthologies identified
    Orthologs in non-Insect Arthropods (via OrthoDB v9.1) ( None identified )
    No non-Insect Arthropod orthologies identified
    Orthologs in non-Arthropod Metazoa (via OrthoDB v9.1) ( None identified )
    No non-Arthropod Metazoa orthologies identified
    Paralogs
    Paralogs (via DIOPT v8.0)
    Drosophila melanogaster (Fruit fly) (9)
    1 of 10
    1 of 10
    1 of 10
    1 of 10
    1 of 10
    1 of 10
    1 of 10
    1 of 10
    1 of 10
    Human Disease Associations
    FlyBase Human Disease Model Reports
      Disease Model Summary Ribbon
      Disease Ontology (DO) Annotations
      Models Based on Experimental Evidence ( 0 )
      Allele
      Disease
      Evidence
      References
      Potential Models Based on Orthology ( 0 )
      Human Ortholog
      Disease
      Evidence
      References
      Modifiers Based on Experimental Evidence ( 0 )
      Allele
      Disease
      Interaction
      References
      Disease Associations of Human Orthologs (via DIOPT v8.0 and OMIM)
      Note that ortholog calls supported by only 1 or 2 algorithms (DIOPT score < 3) are not shown.
      Homo sapiens (Human)
      Gene name
      Score
      OMIM
      OMIM Phenotype
      DO term
      Complementation?
      Transgene?
      Functional Complementation Data
      Functional complementation data is computed by FlyBase using a combination of the orthology data obtained from DIOPT and OrthoDB and the allele-level genetic interaction data curated from the literature.
      Interactions
      Summary of Physical Interactions
      esyN Network Diagram
      Interactions Browser
      Summary of Genetic Interactions
      esyN Network Diagram
      esyN Network Key:
      Suppression
      Enhancement

      Please look at the allele data for full details of the genetic interactions
      Starting gene(s)
      Interaction type
      Interacting gene(s)
      Reference
      Starting gene(s)
      Interaction type
      Interacting gene(s)
      Reference
      External Data
      Subunit Structure (UniProtKB)
      Homodimer.
      (UniProt, Q02910 )
      Linkouts
      DroID - A comprehensive database of gene and protein interactions.
      InterologFinder - Protein-protein interactions (PPI) from both known and predicted PPI data sets.
      MIST (protein-protein) - An integrated Molecular Interaction Database
      Pathways
      Signaling Pathways (FlyBase)
      Metabolic Pathways
      External Data
      Linkouts
      Genomic Location and Detailed Mapping Data
      Chromosome (arm)
      3R
      Recombination map

      3-52

      Cytogenetic map
      Sequence location
      3R:12,162,887..12,166,186 [-]
      FlyBase Computed Cytological Location
      Cytogenetic map
      Evidence for location
      87B1-87B1
      Limits computationally determined from genome sequence between P{EP}Lk6EP886 and P{PZ}svp07842
      Experimentally Determined Cytological Location
      Cytogenetic map
      Notes
      References
      Determined on the basis of RFLP's detected with Df(3R)T-47 and Df(3R)kar-Sz12 using cDNA as probe.
      86E-87B
      (determined by in situ hybridisation)
      87A9-87B5
      (determined by in situ hybridisation)
      Experimentally Determined Recombination Data
      Location

      3-[51]

      Left of (cM)
      Right of (cM)
      Notes
      Stocks and Reagents
      Stocks (14)
      Genomic Clones (35)
      cDNA Clones (63)
       

      Please Note This section lists cDNAs and ESTs that fall within the genomic extent of the gene model, which may include cDNAs and ESTs of genes within introns, or of overlapping genes. Please see GBrowse for alignment of the cDNAs and ESTs to the gene model.

      cDNA clones, fully sequenced
      BDGP DGC clones
      Other clones
      Drosophila Genomics Resource Center cDNA clones

      For each fully sequenced cDNA the DGRC maintains various forms of the cDNA (e.g tagged or untagged) in several different host vectors for subsequent cloning and expression in Drosophila and Drosophila cell lines.

      cDNA Clones, End Sequenced (ESTs)
      RNAi and Array Information
      Linkouts
      DRSC - Results frm RNAi screens
      GenomeRNAi - A database for cell-based and in vivo RNAi phenotypes and reagents
      Antibody Information
      Laboratory Generated Antibodies
       
      Commercially Available Antibodies
       
      Other Information
      Relationship to Other Genes
      Source for database identify of
      Source for database merge of
      Additional comments
      Other Comments

      Cpn is an immobile Ca[2+] buffer localised along the base of the rhabdomere, which is required to prevent light-induced retinal degeneration.

      Class I mutations of Cpn alter the structure of the rhabdomere, class II mutations have rough eyes due to misorientation of the rhabdomeres and photoreceptor cell death. These mutant phenotypes can be rescued by P-element mediated transformation of genomic Cpn DNA.

      Class I mutations of Cpn alter the structure of the rhabdomere, class II mutations have rough eyes due to misorientation of the rhabdomeres and photoreceptor cell death. These mutant phenotypes can be rescued by P-element mediated transformation of genomic Cpn DNA. Analysis of the mutants suggests the Cpn plays important roles in both rhadomere development and photoreceptor cell survival.

      The Cpn protein binds calcium, contains a long C-terminal leucine zipper and is expressed in the soma and axons of all photoreceptor cells, early in development, when cell-type decisions are being made. Cpn expression pattern is unaffected by mutations in the gl gene, which block photoreceptor development.

      Monoclonal antibody 72H5 was used to isolate this protein, which is the same protein as isolated by Martin et al, PNAS 90: 1531--1535, isolated using a different monoclonal antibody, 23E9.

      Monoclonal antibody 23E9 used to identify Cpn calcium binding protein in photoreceptor cells and ocelli: the location of the protein within a distinct cytoplasmic region suggests that it might function as a calcium sequestering "sponge" regulating the amount of free cytoplasmic calcium.

      Origin and Etymology
      Discoverer
      Etymology
      Identification
      External Crossreferences and Linkouts ( 28 )
      Sequence Crossreferences
      NCBI Gene - Gene integrates information from a wide range of species. A record may include nomenclature, Reference Sequences (RefSeqs), maps, pathways, variations, phenotypes, and links to genome-, phenotype-, and locus-specific resources worldwide.
      GenBank Nucleotide - A collection of sequences from several sources, including GenBank, RefSeq, TPA, and PDB.
      GenBank Protein - A collection of sequences from several sources, including translations from annotated coding regions in GenBank, RefSeq and TPA, as well as records from SwissProt, PIR, PRF, and PDB.
      RefSeq - A comprehensive, integrated, non-redundant, well-annotated set of reference sequences including genomic, transcript, and protein.
      UniProt/Swiss-Prot - Manually annotated and reviewed records of protein sequence and functional information
      Other crossreferences
      BDGP expression data - Patterns of gene expression in Drosophila embryogenesis
      Drosophila Genomics Resource Center - Drosophila Genomics Resource Center (DGRC) cDNA clones
      Eukaryotic Promoter Database - A collection of databases of experimentally validated promoters for selected model organisms.
      Fly-FISH - A database of Drosophila embryo and larvae mRNA localization patterns
      FlyMine - An integrated database for Drosophila genomics
      GenomeRNAi - A database for cell-based and in vivo RNAi phenotypes and reagents
      KEGG Genes - Molecular building blocks of life in the genomic space.
      modMine - A data warehouse for the modENCODE project
      Linkouts
      DroID - A comprehensive database of gene and protein interactions.
      DRSC - Results frm RNAi screens
      InterologFinder - Protein-protein interactions (PPI) from both known and predicted PPI data sets.
      MIST (protein-protein) - An integrated Molecular Interaction Database
      Synonyms and Secondary IDs (12)
      Datasets (0)
      Study focus (0)
      Experimental Role
      Project
      Project Type
      Title
      References (50)