MATE transporters

Danbolt, N. C., Storm-Mathisen, J., and Kanner, B. I. (1992) A (Na+ + K+) coupled L-gluta-mate transporter purified from rat brain is located in glial cell processes. Neuroscience 51, 295-310. 

Morita M, Shitan N, Sawada K, Van Montagu MC, Inze D, Rischer H, Goossens A, Oksman-Caldentey KM, Moriyama Y, Yazaki K. (2009) Vacuolar transport of nicotine is mediated by a multidrug and toxic com-ponnd extrnsion (MATE) transporter in Nicotiana tabacum. Proc Natl Acad Sci USA 106 2447-2452. 

Marinova K, Pourcel L, Weder B, Schwarz M, Barron D, Routaboul JM, Debeaujon I, Klein M. 2007a. The Arabidopsis MATE transporter TT12 act as a vacuolar flavonoid/H + -antiporter active in proanthocyanidin-accumulating cells of the seed coat. Plant Cell 19 2023-2038. 

Transporters are integral membrane proteins that typically have 12 transmembrane domains (TMDs), althongh some have 6, 8, 10, 11, 13 or even 17 TMDs. The TMDs are folded in a-heUcal stractures within the membrane and linked at both sides by amino acid seqnences floating in the internal or external cell environment. The amino acids in the external loop domains are freqnently A/-glycosylated, while those of the intracellnlar loops of SLC, ABC and MATE proteins bear phosphorylation sites the ABCs also have one or two ATP-binding domains. The 3D stmcture of TMDs is a crown shape, and they look like a channel allowing communication between the two fluid spaces separated by the lipid bilayer (Figure 34.3). Many SLC and MATE transporters have 300-800 amino acid residues and a molecular... 

The MATE transporters are involved in MDR, preferentially to OCs, via a H or Na -coupled antiport mechanism. In humans, two genes encode MATEl and MATE2. MATEl is ubiquitous throughout the body, but is most abundant in the luminal membrane of the urinary tubules and bile canaliculi in the liver. By contrast, MATE2 is... 

Fig. 2 Two-dimensional model of the Arabidopsis MATE transporter TT12. (a) The prediction of transmembrane helices was performed using ConPred2. Conserved sequence motifs identified by ClutsalW are highlighted by blue boxes and single amino acids conserved in eukaryotic and prokaryotic MATE proteins (black letters) or all Arabidopsis MATE proteins (red letters) are indicated, (b) Weblogo presentation of the conserved Boxes 1-4 using all annotated Arabidopsis MATE protein sequences...

In this respect, it is noteworthy that plants not producing berberine contain a detoxifying berberine efflux transporter the finding that the Arabidopsis MATE transporter AtDTXl catalyzes the efflux of various toxins, including berberine, across the plasmalemma energized by the pH gradient (Li et al, 2002) supports the idea that berberine is an important constituent of soil microenvironments. 

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