Transporters, integral membrane proteins

Single transmembrane helix Ca2+ receptor N terminus in vesicle SNARE proteins, C termini in vesicle Integral membrane protein Integral membrane protein, Cl- transporter Integral membrane protein Integral membrane protein 13 subunits H+ generator... 

Aquaporins (AQP) are a family of integral membrane proteins expressed in all organisms and play a fundamental role in the regulation of water transport into and out of cells. 

Fatty acid transport proteins (FATPs) are an evolutionary conserved family of integral membrane proteins found at the plasma membrane and on internal membranes. FATPs facilitate the unidirectional uptake and/ or intracellular activation of unesterified long-chain and very long-chain fatty acids (LCFAs) into a variety of lipid-metabolizing cells and tissues. 

Glucose transporters are integral membrane proteins that catalyze the permeation of sugars into cells, along or against a concentration gradient. 

In series with a desolvation energy barrier required to disrupt aqueous solute hydrogen bonds [14], the lipid bilayer offers a practically impermeable barrier to hydrophilic solutes. It follows that significant transepithelial transport of water-soluble molecules must be conducted paracellularly or mediated by solute translocation via specific integral membrane proteins (Fig. 6). Transcellular permeability of lipophilic solutes depends on their solubility in GI membrane lipids relative to their aqueous solubility. This lumped parameter, membrane permeability,... 

Figure 4.4 Comparison of oxidase-dependent iron transport in mammals and yeast. In mammals, the plasma glycoprotein cerulpolasmin mediates iron oxidation, facilitating iron export from the cells and delivery to other tissues throughout the body. In yeast, Fet3p, an integral membrane protein mediates iron oxidation, resulting in plasma membrane iron transport through the permease Ftrlp. Reprinted from Askwith and Kaplan, 1998. Copyright (1998), with permission from Elsevier Science.

Secretory carrier membrane Ubiquitous integral membrane proteins of secretory and transport vesicles of unknown function, proteins (SCAMPs)... 

Passage through the Golgi apparatus is obligatory for most proteins destined for fast transport. In all cell types, secretory and integral membrane proteins are synthesized on polysomes bound to the endoplasmic reticulum. Secretory proteins enter the lumen of the reticulum, whereas membrane proteins become oriented within the... 

The Major Facilitator Superfamily (MFS) [95-97] is the largest secondary transporter family known in the genomes sequenced to date [98], These polytopic integral membrane proteins enable the transport of a wide range of solutes, including amino acids, sugars, ions, and toxins. Medically relevant members of the family include the bacterial efflux pumps associated with... 

Rohrbach, M. R., Braun, V. and Koster W. (1995). Ferrichrome transport in Escherichia coli K-12 altered substrate specificity of mutated periplasmic FhuD and interaction of FhuD with the integral membrane protein FhuB, J. Bacteriol., Ill, 7186-7193. 

Koster, W. and Bohm, B. (1992). Point mutations in 2 conserved glycine residues within the integral membrane protein FhuB affect iron (III) hydroxamate transport, Mol. Gen. Genet., 232, 399-407. 

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