Protein Family Models

MIP (Major Intrinsic Protein) family proteins exhibit essentially two distinct types of channel properties: (1) specific water transport by the aquaporins, and (2) small neutral solutes transport, such as glycerol by the glycerol facilitators [1]. [1]. 9655351. Prediction of functional residues in water channels and related proteins. Froger A, Tallur B, Thomas D, Delamarche C;. Protein Sci 1998;7:1458-1468. (from Pfam)

Date:

2024-10-16

MIP (Major Intrinsic Protein)/aquaporin family protein similar to aquaporin that permits osmotically driven movement of water in both directions, and glycerol uptake facilitator protein that mediates glycerol diffusion across the cytoplasmic membrane via a pore-type mechanism

Date:

2024-07-01

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.

Date:

2022-03-28