Editing ABC transporter (section)

=== Prokaryotic ===

Bacterial ABC transporters are essential in cell viability, [[virulence]], and pathogenicity.<ref name=":0" /><ref name=davidson/> Iron ABC uptake systems, for example, are important effectors of virulence.<ref name="pmid7927795">{{cite journal | vauthors = Henderson DP, Payne SM | title = Vibrio cholerae iron transport systems: roles of heme and siderophore iron transport in virulence and identification of a gene associated with multiple iron transport systems | journal = Infection and Immunity | volume = 62 | issue = 11 | pages = 5120–5 | date = Nov 1994 | pmid = 7927795 | pmc = 303233 | doi =  10.1128/IAI.62.11.5120-5125.1994}}</ref> [[Pathogens]] use [[siderophores]], such as [[Enterobactin]], to scavenge iron that is in complex with high-affinity iron-binding proteins or [[erythrocytes]]. These are high-affinity iron-chelating molecules that are secreted by bacteria and reabsorb iron into iron-siderophore complexes. The chvE-gguAB [[gene]] in ''Agrobacterium tumefaciens'' encodes [[glucose]] and [[galactose]] importers that are also associated with virulence.<ref name="pmid2118656">{{cite journal | vauthors = Cangelosi GA, Ankenbauer RG, Nester EW | title = Sugars induce the Agrobacterium virulence genes through a periplasmic binding protein and a transmembrane signal protein | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 87 | issue = 17 | pages = 6708–12 | date = Sep 1990 | pmid = 2118656 | pmc = 54606 | doi = 10.1073/pnas.87.17.6708 | bibcode = 1990PNAS...87.6708C | doi-access = free }}</ref><ref name="pmid9079938">{{cite journal | vauthors = Kemner JM, Liang X, Nester EW | title = The Agrobacterium tumefaciens virulence gene chvE is part of a putative ABC-type sugar transport operon | journal = Journal of Bacteriology | volume = 179 | issue = 7 | pages = 2452–8 | date = Apr 1997 | pmid = 9079938 | pmc = 178989 | doi =  10.1128/jb.179.7.2452-2458.1997}}</ref> Transporters are extremely vital in cell survival such that they function as protein systems that counteract any undesirable change occurring in the cell. For instance, a potential lethal increase in [[osmosis|osmotic]] strength is counterbalanced by activation of osmosensing ABC transporters that mediate uptake of solutes.<ref name="pmid15519310">{{cite journal | vauthors = Poolman B, Spitzer JJ, Wood JM | title = Bacterial osmosensing: roles of membrane structure and electrostatics in lipid-protein and protein-protein interactions | journal = Biochimica et Biophysica Acta (BBA) - Biomembranes | volume = 1666 | issue = 1–2 | pages = 88–104 | date = Nov 2004 | pmid = 15519310 | doi = 10.1016/j.bbamem.2004.06.013 | s2cid = 21763870 | url = https://pure.rug.nl/ws/files/3624524/2004BiochimBiophysActaPoolman.pdf }}</ref> Other than functioning in transport, some bacterial ABC proteins are also involved in the regulation of several physiological processes.<ref name=davidson/>

In bacterial efflux systems, certain substances that need to be extruded from the cell include surface components of the bacterial cell (e.g. capsular polysaccharides, [[lipopolysaccharides]], and [[teichoic acid]]), proteins involved in bacterial pathogenesis (e.g. [[hemolysis]], [[heme]]-binding protein, and alkaline [[protease]]), heme, [[hydrolytic enzymes]], S-layer proteins, competence factors, [[toxins]], [[antibiotics]], [[bacteriocins]], peptide [[antibiotics]], drugs and siderophores.<ref name=davidsonchen>{{cite journal | vauthors = Davidson AL, Chen J | title = ATP-binding cassette transporters in bacteria | journal = Annual Review of Biochemistry | volume = 73 | pages = 241–68 | year = 2004 | pmid = 15189142 | doi = 10.1146/annurev.biochem.73.011303.073626 }}</ref> They also play important roles in biosynthetic pathways, including extracellular polysaccharide biosynthesis<ref name="pmid9575204">{{cite journal | vauthors = Zhou Z, White KA, Polissi A, Georgopoulos C, Raetz CR | title = Function of Escherichia coli MsbA, an essential ABC family transporter, in lipid A and phospholipid biosynthesis | journal = The Journal of Biological Chemistry | volume = 273 | issue = 20 | pages = 12466–75 | date = May 1998 | pmid = 9575204 | doi = 10.1074/jbc.273.20.12466 | doi-access = free | hdl = 2434/611267 | hdl-access = free }}</ref> and [[cytochrome]] biogenesis.<ref name="pmid8181727">{{cite journal | vauthors = Poole RK, Gibson F, Wu G | title = The cydD gene product, component of a heterodimeric ABC transporter, is required for assembly of periplasmic cytochrome c and of cytochrome bd in Escherichia coli | journal = FEMS Microbiology Letters | volume = 117 | issue = 2 | pages = 217–23 | date = Apr 1994 | pmid = 8181727 | doi = 10.1111/j.1574-6968.1994.tb06768.x | doi-access = free }}</ref>