|Function||MIP family channel proteins|
|Domain Trusted Cutoff||171.25|
|Domain Noise Cutoff||123.00|
|Mainrole Category||Transport and binding proteins|
|Subrole Category||Unknown substrate|
|Author||Paulsen IT, Saier MH, Loftus BJ|
|Entry Date||Aug 11 2000 1:26PM|
|Last Modified||Feb 14 2011 3:27PM|
|Comment||1.A.8 The Major Intrinsic Protein (MIP) Family
The MIP family is large and diverse, possessing over 100 members that all form transmembrane channels. These channel proteins function in water, small
carbohydrate (e.g., glycerol), urea, NH3, CO2 and possibly ion transport by an energy independent mechanism. They are found ubiquitously in bacteria, archaea
and eukaryotes. The MIP family contains two major groups of channels: aquaporins and glycerol facilitators.
The known aquaporins cluster loosely together as do the known glycerol facilitators. MIP family proteins are believed to form aqueous pores that selectively allow passive transport of their solute(s) across the membrane with minimal apparent recognition. Aquaporins selectively transport water (but not glycerol) while glycerol facilitators selectively transport glycerol but not water. Some aquaporins can transport NH3 and CO2. Glycerol facilitators function as solute nonspecific channels, and may transport glycerol, dihydroxyacetone, propanediol, urea and other small neutral molecules in physiologically important
processes. Some members of the family, including the yeast FPS protein (TC #1.A.8.5.1) and tobacco NtTIPA may transport both water and small solutes.
DR HAMAP; MF_01146; 26 of 27|
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