Resistance gene products, function

Kamimoto Y, Gatmaitan Z, Hsu J, et al. The function of Gpl70, the multidrug resistance gene product, in rat liver canalicular membrane vesicles. J Biol Chem 1989 264 11693 11698. 

Except for its narrow specificity, the ATRI gene product shares a number of properties with the higher eukaryotic MDR proteins responsible for multidrug resistance in tumour cells. The MDR gene products are also transmembrane proteins which seem to function as ATP-dependent drug-efflux pumps pumping out a variety of structurally unrelated compounds (see [25,26]). 

Next, Reilly et al. [65] localized the Na /H exchanger gene product in renal epithelial cells where the distributions of the kinetic isoforms was well-established. The strategy was based on the observation that the resistant- and sensitive-types are restricted to the apical and basolateral membranes, respectively, in confluent LLC-PK]/Clone 4 cells [8]. Thus, if proteins encoded by the cloned cDNAs localized to the apical membrane this would indicate that they represent the resistant-type. Localization to the basolateral membrane would prove they were the sensitive-type and presence on both membranes would suggest that the two functional isoforms had identical primary structures. Na exchanger proteins were localized by... 

Phytoalexins are an Important component of the plant disease defense reaction called the hypersensitive response. Successful pathogens have evolved methods for dealing with plant phytoalexins. Including suppressors of their production, detoxification of the phytoalexins and In some cases avoiding elaboration of substances, called elicitors, that would otherwise Initiate the defense reaction. Elicitors obtained from pathogens are of considerable utility for study of various aspects of plant biology because of their interaction with the products of plant disease resistance genes. Substantial information has been obtained on how elicitors are perceived by plant cells and how they function, but much remains to be done. Finally, elicitors may prove of value for the economic production of exotic plant secondary metabolites and as specific herbicides. 

Figure 10 The silver resistance genes, transcripts and the organization of the protein products in the membrane of Salmonella (a). Top line shows the mRNAs. The open boxes indicate different genes or open reading frames (ORFs) and their orientations. The nucleotides between the genes (nt) and the amino acids of the proteins (AA) are indicated, (b). The proposed functions and organization of the protein products relative to the bacterial structure are indicated. (Ref 71. Reproduced by permission of Nature Publishing Group (www.namre.com))...

---