Cholera toxin (also known as choleragen and sometimes abbreviated to CTX , Ctx or CT ) is an AB5 multimeric protein complex secreted by the bacterium Vibrio cholerae . CTX is responsible for the massive, watery diarrhea characteristic of cholera infection. It is a member of the heat-labile enterotoxin family .
29-779: [REDACTED] Look up CT , c.t. , or Ct. in Wiktionary, the free dictionary. CT or ct may refer to: In arts and media [ edit ] c't ( Computer Technik ), a German computer magazine Freelancer Agent Connecticut (C.T.) , a fictional character in the web series Red vs. Blue Christianity Today , an American evangelical Christian magazine Businesses and organizations [ edit ] CT Corp , an Indonesian conglomerate CT Corporation , an umbrella brand for two businesses: CT Corporation and CT Liena C/T Group , formerly Crosby Textor Group, social research and political polling company Canadian Tire ,
58-712: A Canadian company engaged in retailing, financial services and petroleum Calgary Transit , the public transit service in Calgary, Alberta, Canada Central Trains (National Rail abbreviation), a former train operating company in the United Kingdom Czech Television , the public television broadcaster in the Czech Republic Community Transit , the public transit service in Snohomish County, Washington, U.S. Comunión Tradicionalista ,
87-486: A German physician and microbiologist, was the first person to postulate the existence of cholera toxin. In 1886, Koch proposed that Vibrio cholerae secreted a substance which caused the symptoms of cholera . Koch's postulation was proven correct by Indian microbiologist Sambhu Nath De , who in 1951 studied and documented the effects of injecting rabbits with heat-killed cholera bacteria. He concluded from this experiment that an endotoxin liberated upon disintegration of
116-526: A cardboard (e.g. zucchini 3 ct) Corps Turd, etymologically "Cadet in Training", member of the Texas A&;M Corps of Cadets that is not in the band See also [ edit ] Champions Trophy (disambiguation) , several trophies awarded in different sports Central tendon (disambiguation) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with
145-437: A filamentous " satellite " phage, including elements for replication (RstA), integration (RstB), preventing repression of CTXφ replication (RstC) and regulation of gene expression (RstR), as well as genes coding for proteins needed for phage packaging and secretion (Psh, Cep, OrfU, Ace and Zot), which are very similar to the genes of Ff filamentous coliphages . These genes (and others) enable the replication and later secretion of
174-761: A former Spanish political party CT (TV channel) , a Filipino cable and satellite television network Finance [ edit ] Centime (ct), the French for "cent", used in English in several Francophone countries Stotinki (ст), the currency of Bulgaria Places [ edit ] CT postcode area , for Canterbury and surrounding areas in south-eastern England Connecticut (United States postal abbreviation) Province of Catania (vehicle registration code), Sicily, Italy Central African Republic (FIPS Pub 10-4 code and obsolete NATO diagram) Canton and Enderbury Islands (obsolete ISO 3166 country code), part of
203-607: A marker, we can get a better understanding of the properties and functions of lipid rafts. Endocytosis is broadly divided into clathrin -dependent and clathrin-independent process, and the cholera toxin utilizes both pathways. Cholera toxin has been shown to enter cells via endocytosis in multiple pathways. These pathways include caveolae , clathrin-coated pits, clathrin-independent carriers (CLICs), and GPI -Enriched Endocytic Compartments ( GEECs ) pathway, ARF6 -mediated endocytosis and Fast Endophilin-Mediated Endocytosis (FEME). How cholera toxin triggers these endocytosis pathways
232-399: A measure in the cycle of quantification/qualification of a real-time polymerase chain reaction Carat (purity) (ct), a measure of the purity of gold and platinum alloys Carat (mass) (ct), a unit of mass used for measuring gems and pearls Continuous-time signal , a varying quantity (a signal) whose domain is a continuum Center tap , a wire that is connected halfway along one of
261-711: A result of ubiquitination . CTA1 is then free to bind with a human partner protein called ARF6 (ADP-ribosylation factor 6); binding to Arf6 drives a change in the shape of CTA1 which exposes its active site and enables its catalytic activity. The CTA1 fragment catalyses ADP-ribosylation of the Gs alpha subunit (Gα s ) proteins using NAD . The ADP-ribosylation causes the Gα s subunit to lose its catalytic activity of GTP hydrolysis into GDP + P i , thus maintaining Gα s in its activated state. Increased Gα s activation leads to increased adenylate cyclase activity, which increases
290-633: A time zone in Canada, the United States, and Mexico Coffin Texts Conspiracy theory or theorist Counter-terrorism Cryptologic technician , a United States Navy enlisted rating or job specialty Chinese Taipei , the name used by Taiwan in some international organizations due to political pressure from the People's Republic of China ct followed by a number means the number of items contained in
319-432: A toxic protein secreted by Vibrio cholerae Threshold Cycle (C t ), see cycle of quantification/qualification COVID-19 test Computing [ edit ] Intel Ct , a SIMD multithreading programming model developed by Intel Certificate Transparency , in network security Other uses in science and technology [ edit ] CT Value , in drinking water disinfection Threshold cycle (C t ),
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#1732845141041348-619: Is moved to the Golgi apparatus , where the A1 protein is recognized by the endoplasmic reticulum (ER) chaperone , protein disulfide isomerase . The A1 chain is then unfolded and delivered to the membrane, where Ero1 triggers the release of the A1 protein by oxidation of protein disulfide isomerase complex. As the A1 protein moves from the ER into the cytoplasm by the Sec61 channel, it refolds and avoids deactivation as
377-619: Is needed. This may allow for CTB to be used as an adjuvant for vaccinating against many kinds of diseases. This may include bacterial and viral infections, allergy and diabetes. Of note, as CTB has shown to induce mucosal humoral immune responses , vaccines against mucosal viruses such as HIV are a potential target. Since cholera toxin has been shown to preferentially bind to GM1 gangliosides, this characteristic can be utilized for membrane studies. Lipid rafts are difficult to study as they vary in size and lifetime, as well being part of an extremely dynamic component of cells. Using cholera toxin β as
406-425: Is not fully understood, but the fact that cholera toxin triggers these pathways shows the use of the toxin as an important marker to investigate these mechanisms. One of the most important aspects of cholera toxin is the retrograde traffic mechanism that transports the toxin from the cell membrane back to the trans-Golgi network and the endoplasmic reticulum. Since both cholera toxin and GM1 species can be tagged with
435-615: Is routinely used as a neuronal tracer . Treatment of cultured rodent neural stem cells with cholera toxin induces changes in the localization of the transcription factor Hes3 and increases their numbers. GM1 gangliosides are found in lipid rafts on the cell surface. B subunit complexes labelled with fluorescent tags or subsequently targeted with antibodies can be used to identify rafts. There are currently two vaccines for cholera: Dukoral and Shanchol. Both vaccines use whole killed V. cholerae cells however, Dukoral also contains recombinant cholera toxin β (rCTB). Some studies suggest that
464-432: The B subunit (part B, receptor binding, P01556 ), denoted as AB 5 . Subunit B binds while subunit A activates the G protein which activates adenylate cyclase . The three-dimensional structure of the toxin was determined using X-ray crystallography by Zhang et al. in 1995. The five B subunits—each weighing 11 kDa , form a five-membered ring. The A subunit which is 28 kDa, has two important segments. The A1 portion of
493-421: The B subunit ring of the cholera toxin binds to GM1 gangliosides on the surface of target cells. If a cell lacks GM1, the toxin most likely binds to other types of glycans , such as Lewis Y and Lewis X , attached to proteins instead of lipids. Once bound, the entire toxin complex is endocytosed by the cell and the reduction of a disulfide bridge releases the cholera toxin A1 (CTA1) chain. The endosome
522-457: The CTXφ bacteriophage, facilitating the horizontal gene transfer of CTXφ to other susceptible cells without requiring excision of the prophage from the original host bacterium, transmitting the gene encoding CTX together with the remainder of the phage genome. Because the B subunit appears to be relatively non-toxic, researchers have found a number of applications for it in cell and molecular biology. It
551-638: The Phoenix Islands in the Pacific Ocean Cape Town (capital city of the Western Cape, South Africa) Ct, for "Court"; a street suffix as used in the US Science and technology [ edit ] Biology and medicine [ edit ] Haplogroup CT , Y-DNA haplogroup. CT scan or X-ray computed tomography, a medical imaging method Calcitonin (symbol CT), a hormone produced in
580-470: The Space Shuttle from Vehicle Assembly Building to Launch Complex 39 Civil Air Transport (IATA code) Training cruiser , a U.S. Navy hull classification Cybertruck Other uses [ edit ] Ct, a typographic ligature c. t. (cum tempore, Latin for "with time"), indicates that a lecture will begin a quarter-hour after the stated time; see Academic quarter Central Time Zone ,
609-442: The bacteria was the cause of the symptoms of cholera. In 1959, De conducted another experiment, this time using a bacteria-free culture filtrate from V. cholerae injected into the small intestines of rabbits. The resulting build up of fluid in the intestines conclusively proved the existence of a toxin. The complete toxin is a hexamer made up of a single copy of the A subunit (part A, enzymatic, P01555 ), and five copies of
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#1732845141041638-518: The chain (CTA1) is a globular enzyme payload that ADP-ribosylates G proteins , while the A2 chain (CTA2) forms an extended alpha helix which sits snugly in the central pore of the B subunit ring. This structure is similar in shape, mechanism, and sequence to the heat-labile enterotoxin secreted by some strains of the Escherichia coli bacterium. Cholera toxin acts by the following mechanism: First,
667-405: The entry of Na and consequently the entry of water into enterocytes are diminished. The combined effects result in rapid fluid loss from the intestine, up to 2 liters per hour, leading to severe dehydration and other factors associated with cholera, including a rice-water stool . The pertussis toxin (also an AB 5 protein) produced by Bordetella pertussis acts in a similar manner with
696-536: The exception that it ADP-ribosylates the Gα i subunit , rendering it unable to inhibit cAMP production. The gene encoding the cholera toxin was introduced into V. cholerae by horizontal gene transfer . Virulent strains of V. cholerae (the O1 and O139 serogroups ) hold genes from a virus known as the CTXφ bacteriophage . The integrated CTXφ genome contains many of the genes of RS1,
725-522: The inclusion of rCTB may improve vaccine efficacy in young children (2-10) and increase the duration of protection. This is countered by the costs of protecting and storing rCTB against degradation. Another application of the CTB subunit may be as a vaccine adjuvant to other vaccines. It has been shown that coupling CTB and antigens improves the response of the vaccine. Currently the adjuvant potential of CTB has been shown in large animal models so further research
754-430: The intracellular concentration of 3',5'-cyclic AMP (cAMP) to more than 100-fold over normal and over-activates cytosolic PKA . These active PKA then phosphorylate the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel proteins, which leads to ATP -mediated efflux of chloride ions and leads to secretion of H 2 O , Na , K , and HCO 3 into the intestinal lumen . In addition,
783-408: The thyroid gland Calibrated automated thrombogram (CT or CAT), a coagulation test Cardiothoracic surgery , the field of medicine specializing in chest surgery Chemotype (ct.), a chemically distinct entity in a plant or microorganism Cognitive therapy , a type of psychotherapy Connective tissue , a type of biological tissue Chelation therapy Chemotherapy Cholera toxin ,
812-661: The title CT . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=CT&oldid=1252933273 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages CT">CT The requested page title contains unsupported characters : ">". Return to Main Page . Cholera toxin Robert Koch ,
841-423: The windings of a transformer, inductor or a resistor Compliant Tower , a deepwater offshore oil platform Convective temperature , in atmospheric science Current transformer , a kind of transformer used in the electrical power industry Transportation [ edit ] Lexus CT , an automobile Honda CT series , a series of Honda bikes Crawler-transporter , a tracked vehicle used to transport
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