P06624 · MIP_BOVIN

  • Protein
    Lens fiber major intrinsic protein
  • Gene
    MIP
  • Status
    UniProtKB reviewed (Swiss-Prot)
  • Amino acids
  • Protein existence
    Evidence at protein level
  • Annotation score
    5/5

Function

function

Aquaporins form homotetrameric transmembrane channels, with each monomer independently mediating water transport across the plasma membrane along its osmotic gradient (PubMed:23893133, PubMed:30790544).
Specifically expressed in lens fiber cells, this aquaporin is crucial for maintaining lens water homeostasis and transparency. Beyond water permeability, it also acts as a cell-to-cell adhesion molecule, forming thin junctions between lens fiber cells that are essential for maintaining the ordered structure and transparency of the lens (By similarity).

Catalytic activity

Activity regulation

The water channel activity is inhibited by calcium through calmodulin/CALM.

Features

Showing features for site.

126320406080100120140160180200220240260
TypeIDPosition(s)Description
Site149Important for water channel gating
Site246Interaction with BFSP1
Site250interaction with BFSP1

GO annotations

AspectTerm
Cellular Componentapical plasma membrane
Cellular Componentendoplasmic reticulum
Cellular Componentgap junction
Cellular Componentplasma membrane
Molecular Functioncalmodulin binding
Molecular Functionstructural constituent of eye lens
Molecular Functionwater channel activity
Biological Processgap junction-mediated intercellular transport
Biological Processlens development in camera-type eye
Biological Processpositive regulation of cell adhesion
Biological Processprotein homotetramerization
Biological Processvisual perception
Biological Processwater transport

Keywords

Enzyme and pathway databases

Protein family/group databases

Names & Taxonomy

Protein names

  • Recommended name
    Lens fiber major intrinsic protein
  • Alternative names
    • Aquaporin-0
    • MIP26 (MP26
      )

Gene names

    • Name
      MIP

Organism names

  • Taxonomic identifier
  • Taxonomic lineage
    Eukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Mammalia > Eutheria > Laurasiatheria > Artiodactyla > Ruminantia > Pecora > Bovidae > Bovinae > Bos

Accessions

  • Primary accession
    P06624

Proteomes

Organism-specific databases

Subcellular Location

Cell membrane
; Multi-pass membrane protein
Cell junction
Note: Localizes to thin cell-cell junctions in lens fiber cells.

Features

Showing features for topological domain, transmembrane, intramembrane.

TypeIDPosition(s)Description
Topological domain1-9Cytoplasmic
Transmembrane10-29Helical; Name=1
Topological domain30-41Extracellular
Transmembrane42-59Helical; Name=2
Topological domain60-61Cytoplasmic
Intramembrane62-77Discontinuously helical
Topological domain78-82Cytoplasmic
Transmembrane83-106Helical; Name=3
Topological domain107-127Extracellular
Transmembrane128-148Helical; Name=4
Topological domain149-156Cytoplasmic
Transmembrane157-175Helical; Name=5
Topological domain176-178Extracellular
Intramembrane179-193Discontinuously helical
Topological domain194-200Extracellular
Transmembrane201-222Helical; Name=6
Topological domain223-263Cytoplasmic

Keywords

Phenotypes & Variants

Features

Showing features for mutagenesis.

TypeIDPosition(s)Description
Mutagenesis149Increases constitutive water permeability. Abolishes regulation by cytoplasmic calcium levels.
Mutagenesis149Strongly decreases water permeability. Abolishes regulation by cytoplasmic calcium levels.
Mutagenesis149Slightly decreases water permeability, but has a minor effect on the regulation by cytoplasmic calcium levels.
Mutagenesis227Strongly reduced CALM binding.
Mutagenesis230Strongly reduced CALM binding.

Variants

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The viewer provides 89 variants from UniProt as well as other sources including ClinVar and dbSNP.

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PTM/Processing

Features

Showing features for chain, modified residue.

TypeIDPosition(s)Description
ChainPRO_00000639101-263Lens fiber major intrinsic protein
Modified residue235Phosphoserine
Modified residue243Phosphoserine; by PKA
Modified residue245Phosphoserine
Modified residue246Deamidated asparagine

Post-translational modification

Fatty acylated at Met-1 and Lys-238. The acyl modifications, in decreasing order of ion abundance, are: oleoyl (C18:1) > palmitoyl (C16:0) > stearoyl (C18:0) > eicosenoyl (C20:1) > dihomo-gamma-linolenoyl (C20:3) > palmitoleoyl (C16:1) > eicosadienoyl (C20:2).
Subject to partial proteolytic cleavage in the eye lens core. Partial proteolysis promotes interactions between tetramers from adjoining membranes.

Keywords

Proteomic databases

PTM databases

Expression

Tissue specificity

Major component of lens fiber junctions.

Developmental stage

Higher expression in pre-natal (1-5 months gestation) than in postnatal (4-6 months) calf lens.

Gene expression databases

Interaction

Subunit

Homotetramer; each monomer provides an independent water pore (PubMed:15377788, PubMed:16309700).
Two homotetramers on opposing membranes can dimerize, forming a cell-cell junction (PubMed:15377788, PubMed:16309700).
Interacts with CALM; the calcium-calmodulin/CALM complex interacts with the cytoplasmic domains of two aquaporins, leading to channel closure (PubMed:23893133).
Interacts with BFSP1 (via C-terminus); prevents calcium-dependent inhibition of the water channel activity (PubMed:28259670, PubMed:30790544).

Protein-protein interaction databases

Family & Domains

Features

Showing features for motif, region.

TypeIDPosition(s)Description
Motif68-70NPA 1
Motif184-186NPA 2
Region227-237Interaction with CALM
Region239-263Disordered

Domain

Aquaporins contain two tandem repeats each containing three membrane-spanning domains and a pore-forming loop with the signature motif Asn-Pro-Ala (NPA).

Sequence similarities

Belongs to the MIP/aquaporin (TC 1.A.8) family.

Keywords

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    263
  • Mass (Da)
    28,223
  • Last updated
    1988-01-01 v1
  • Checksum
    E08C2C4F33398D4E
MWELRSASFWRAICAEFFASLFYVFFGLGASLRWAPGPLHVLQVALAFGLALATLVQAVGHISGAHVNPAVTFAFLVGSQMSLLRAICYMVAQLLGAVAGAAVLYSVTPPAVRGNLALNTLHPGVSVGQATIVEIFLTLQFVLCIFATYDERRNGRLGSVALAVGFSLTLGHLFGMYYTGAGMNPARSFAPAILTRNFTNHWVYWVGPVIGAGLGSLLYDFLLFPRLKSVSERLSILKGSRPSESNGQPEVTGEPVELKTQAL

Features

Showing features for sequence conflict.

TypeIDPosition(s)Description
Sequence conflict14in Ref. 2; AA sequence
Sequence conflict29-33in Ref. 2; AA sequence

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
K02818
EMBL· GenBank· DDBJ
AAA30622.1
EMBL· GenBank· DDBJ
mRNA

Genome annotation databases

Similar Proteins

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