Major intrinsic proteins

AQPO, formerly known as the Major Intrinsic Protein of 26 kDa (MDP26), is specifically expressed in the plasma membrane of eye lens fiber cells. It transports water to a low degree, but has also been implicated in cell adhesion and gap junction formation. Its main role is to maintain the transparency of the lens by maintaining a tight cellular connection to neighboring cells and/or by controlling the fluid circulation. 

Gorin, M. B., Yancey, S. B., Cline, J., Revel, J. P. and Horwitz, J. (1984). The major intrinsic protein (MIP) of the bovine lens fiber membrane characterization and structure based on cDNA cloning, Cell, 39, 49-59. 

Baker, M.E. Saier, M.H. (1990). A common ancestor for bovine lens fiber major intrinsic protein, soybean nodulin-26 protein, and E. coli glycerol facilitator. Cell 60, 185-6. 

The major intrinsic protein (MIP) of the eye lens, once thought to play a primary role as a gap junction between cells of the eye lens, a biophysically characterized aqueous channel that formed arrays in the eye lens (Gorin et al., 1984), was brought back to the fold as AQP-0. Many of the AQPs in eukaryotes are regulated by phosphorylation, pH, osmolarity, or binding of other proteins or ligands (Anthony et al., 2000 Engel et al., 2000). 

Hasler, L., Walz, T., Tittmann, P., Gross, H., Kistler.J., and Engel, A. (1998b). Purified lens major intrinsic protein (MIP) forms highly ordered tetragonal two-dimensional arrays by reconstitution. / Mol. Biol. 279, 855-864. 

Bienert, G. P., Schussler, M. D., Jahn, T. P. (2008). Metalloids essential, beneficial or toxic Major intrinsic proteins sort it out. Trends in Biochemical Sciences, 33, 20—26. 

Voltage-gated ion channel VIC superfamily Voltage-gated channel Ryanodine/IPs receptor Ca channel Major intrinsic protein family Aquaporins... 

The MIP (major intrinsic protein TC 1.A.8 in the Transporter Classification Database (TCDB www.tcdb.org)) family of aquaporins and glycerol facilitators were found in the 11 bacteria originally studied. Proteins in this family facilitate the passage of several neutral molecules such as water, glycerol, dihydroxyacetone, CO, urea, and ammonia (Jensen et al. 2002 Carbrey et al. 2003 Uehlein et al. 2003). All the microorganisms analyzed have at least one member of this family while some have up to five members (Table 4.1). 

Choi, W. G., and Roberts, D.M. 2007. Arabidopsis NIP2 1, a major intrinsic protein transport - of lactic add induced... 

Major intrinsic protein (MIP26) (bovine lens fiber membranes) Protein-detergent complex... 

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