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1.A.8.8.2
The lens fiber MIP aquaporin (Aqp0) of B. taurus (forms membrane junctions in vivo and double layered crystals in vitro that resemble the in vivo junctions). The water pore is closed in the in vitro structure (Gonen et al., 2004b). It interacts directly with the intracellular loop of connexin 45.6 via its C-terminal extension (Yu et al., 2005). Forms human cataract lens membranes (Buzhynskyy et al., 2007; Yang et al., 2011).  A mutation that causes congenital dominant lens cataracts has been identified (Varadaraj et al. 2008). AqpO catalyzes Zn2+-modulated water permeability as a cooperative tetramer (Nemeth-Cahalan et al., 2007). It transports ascorbic acid (Nakazawa et al., 2011). The Detergent organization around solubilized aquaporin-0 using Small Angle X-ray Scattering has been reported (Berthaud et al., 2012).  Aquaporin 0 (AQP0) in the eye lens is truncated by proteolytic cleavage during lens maturation. This truncated AQP0 is no longer a water channel (Berthaud et al. 2015).  A mutation that causes congenital dominant lens cataracts has been identified (Varadaraj et al. 2008). Cataractogenesis in MIP mutants are probably caused by defects in MIP gene expression in mice (Takahashi et al. 2017). This may be caused by the ability of Aqp0 (as well as Aqp1 and Aqp5) to transport hydrogen peroxide (H2O2) which can cause cataracts (Varadaraj and Kumari 2020).  An automated data processing and analysis pipeline for transmembrane proteins including Aqp0 in detergent solutions has been presented (Molodenskiy et al. 2020).

Accession Number:P06624
Protein Name:MIP aka MIP26
Length:263
Molecular Weight:28223.00
Species:Bos taurus (Bovine) [9913]
Number of TMSs:6
Location1 / Topology2 / Orientation3: Cell membrane1 / Multi-pass membrane protein2
Substrate water

Cross database links:

RefSeq: NP_776362.1   
Entrez Gene ID: 280859   
Pfam: PF00230   
KEGG: bta:280859   

Gene Ontology

GO:0005921 C:gap junction
GO:0016021 C:integral to membrane
GO:0005212 F:structural constituent of eye lens
GO:0055085 P:transmembrane transport

References (4)

[1] “The major intrinsic protein (MIP) of the bovine lens fiber membrane: characterization and structure based on cDNA cloning.”  Gorin M.B.et.al.   6207938
[2] “Sequence analysis of peptide fragments from the intrinsic membrane protein of calf lens fibers MP26 and its natural maturation product MP22.”  Ngoc L.D.et.al.   3882455
[3] “Amino acid sequence of in vivo phosphorylation sites in the main intrinsic protein (MIP) of lens membranes.”  Lampe P.D.et.al.   2176601
[4] “Complete map and identification of the phosphorylation site of bovine lens major intrinsic protein.”  Schey K.L.et.al.   9375569
Structure:
1YMG   2B6P   2C32   1sor   2b6o   3m9i     

External Searches:

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Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MWELRSASFW RAICAEFFAS LFYVFFGLGA SLRWAPGPLH VLQVALAFGL ALATLVQAVG 
61:	HISGAHVNPA VTFAFLVGSQ MSLLRAICYM VAQLLGAVAG AAVLYSVTPP AVRGNLALNT 
121:	LHPGVSVGQA TIVEIFLTLQ FVLCIFATYD ERRNGRLGSV ALAVGFSLTL GHLFGMYYTG 
181:	AGMNPARSFA PAILTRNFTN HWVYWVGPVI GAGLGSLLYD FLLFPRLKSV SERLSILKGS 
241:	RPSESNGQPE VTGEPVELKT QAL