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TAS1R1
Taste receptor type 1 member 1 is a protein that in humans is encoded by the ''TAS1R1'' gene. Structure The protein encoded by the ''TAS1R1'' gene is a G protein-coupled receptor with seven trans-membrane domains and is a component of the heterodimeric amino acid taste receptor T1R1+3. This receptor is formed as a dimer of the TAS1R1 and TAS1R3 proteins. Moreover, the TAS1R1 protein is not functional outside of formation of the 1+3 heterodimer. The TAS1R1+3 receptor has been shown to respond to L-amino acids but not to their D-enantiomers or other compounds. This ability to bind L-amino acids, specifically L-glutamine, enables the body to sense the umami, or savory, taste. Multiple transcript variants encoding several different isoforms have been found for this gene, which may account for differing taste thresholds among individuals for the umami taste. Another interesting quality of the TAS1R1 and TAS1R2 proteins is their spontaneous activity in the absence of the extracellular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TAS1R3
Taste receptor type 1 member 3 is a protein that in humans is encoded by the ''TAS1R3'' gene. The ''TAS1R3'' gene encodes the human homolog of mouse Sac taste receptor, a major determinant of differences between sweet-sensitive and -insensitive mouse strains in their responsiveness to sucrose, saccharin, and other sweeteners. Structure The protein encoded by the ''TAS1R3'' gene is a G protein-coupled receptor with seven trans-membrane domains and is a component of the heterodimeric amino acid taste receptor TAS1R1+3 and sweet taste receptor TAS1R2+3. This receptor is formed as a protein dimer with either TAS1R1 or TAS1R2. Experiments have also shown that a homo-dimer of TAS1R3 is also sensitive to natural sugar substances. This has been hypothesized as the mechanism by which sugar substitutes do not have the same taste qualities as natural sugars. Ligands The G protein-coupled receptors for sweet and umami taste are formed by dimers of the TAS1R proteins. The TAS1R1+3 ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TAS1R2
Taste receptor type 1 member 2 is a protein that in humans is encoded by the ''TAS1R2'' gene. The sweet taste receptor is predominantly formed as a dimer of T1R2 and T1R3 by which different organisms sense this taste. In songbirds, however, the T1R2 monomer does not exist, and they sense the sweet taste through the umami taste receptor (T1R1 and T1R3) as a result of an evolutionary change that it has undergone. Structure The protein encoded by the ''TAS1R2'' gene is a G protein-coupled receptor with seven trans-membrane domains and is a component of the heterodimeric amino acid taste receptor T1R2+3. This receptor is formed as a dimer of the TAS1R2 and TAS1R3 proteins. Moreover, the TAS1R2 protein is not functional without formation of the 2+3 heterodimer. Another interesting quality of these receptors expressed by ''TAS1R2'' and ''TAS1R1'' genes, is their spontaneous activity in the absence of the extracellular domains and binding ligands. This may mean that the extracellular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taste Receptor
A taste receptor or tastant is a type of cellular receptor which facilitates the sensation of taste. When food or other substances enter the mouth, molecules interact with saliva and are bound to taste receptors in the oral cavity and other locations. Molecules which give a sensation of taste are considered "sapid". Vertebrate taste receptors are divided into two families: * Type 1, sweet, first characterized in 2001: – * Type 2, bitter, first characterized in 2000: In humans there are 25 known different bitter receptors, in cats there are 12, in chickens there are three, and in mice there are 35 known different bitter receptors. Visual, olfactive, "sapictive" (the perception of tastes), trigeminal (hot, cool), mechanical, all contribute to the perception of ''taste''. Of these, transient receptor potential cation channel subfamily V member 1 (TRPV1) vanilloid receptors are responsible for the perception of heat from some molecules such as capsaicin, and a CMR1 receptor is r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umami
Umami ( from ja, 旨味 ), or savoriness, is one of the five basic tastes. It has been described as savory and is characteristic of broths and cooked meats. People taste umami through taste receptors that typically respond to glutamates and nucleotides, which are widely present in meat broths and fermented products. Glutamates are commonly added to some foods in the form of monosodium glutamate (MSG), and nucleotides are commonly added in the form of disodium guanylate, inosine monophosphate (IMP) or guanosine monophosphate (GMP). Since umami has its own receptors rather than arising out of a combination of the traditionally recognized taste receptors, scientists now consider umami to be a distinct taste. Foods that have a strong umami flavor include meats, shellfish, fish (including fish sauce and preserved fish such as maldive fish, '' Katsuobushi'', sardines, and anchovies), tomatoes, mushrooms, hydrolyzed vegetable protein, meat extract, yeast extract, cheeses, and soy s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taste Receptor
A taste receptor or tastant is a type of cellular receptor which facilitates the sensation of taste. When food or other substances enter the mouth, molecules interact with saliva and are bound to taste receptors in the oral cavity and other locations. Molecules which give a sensation of taste are considered "sapid". Vertebrate taste receptors are divided into two families: * Type 1, sweet, first characterized in 2001: – * Type 2, bitter, first characterized in 2000: In humans there are 25 known different bitter receptors, in cats there are 12, in chickens there are three, and in mice there are 35 known different bitter receptors. Visual, olfactive, "sapictive" (the perception of tastes), trigeminal (hot, cool), mechanical, all contribute to the perception of ''taste''. Of these, transient receptor potential cation channel subfamily V member 1 (TRPV1) vanilloid receptors are responsible for the perception of heat from some molecules such as capsaicin, and a CMR1 receptor is r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G Protein-coupled Receptors
G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large group of evolutionarily-related proteins that are cell surface receptors that detect molecules outside the cell and activate cellular responses. Coupling with G proteins, they are called seven-transmembrane receptors because they pass through the cell membrane seven times. Text was copied from this source, which is available under Attribution 2.5 Generic (CC BY 2.5) license. Ligands can bind either to extracellular N-terminus and loops (e.g. glutamate receptors) or to the binding site within transmembrane helices (Rhodopsin-like family). They are all activated by agonists although a spontaneous auto-activation of an empty receptor can also be observed. G protein-coupled receptors are found only in eukaryotes, including yeast, choanoflagellates, and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossopharyngeal Nerve
The glossopharyngeal nerve (), also known as the ninth cranial nerve, cranial nerve IX, or simply CN IX, is a cranial nerve that exits the brainstem from the sides of the upper Medulla oblongata, medulla, just anterior (closer to the nose) to the vagus nerve. Being a mixed nerve (sensorimotor), it carries afferent sensory and efferent motor information. The motor division of the glossopharyngeal nerve is derived from the Basal plate (neural tube), basal plate of the embryonic medulla oblongata, whereas the sensory division originates from the cranial neural crest. Structure From the anterior portion of the medulla oblongata, the glossopharyngeal nerve passes laterally across or below the Flocculus (cerebellar), flocculus, and leaves the skull through the central part of the jugular foramen. From the superior and inferior ganglia in jugular foramen, it has its own sheath of dura mater. The inferior ganglion on the inferior surface of petrous part of temporal is related with a tri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chorda Tympani
The chorda tympani is a branch of the facial nerve that originates from the taste buds in the front of the tongue, runs through the middle ear, and carries taste messages to the brain. It joins the facial nerve (cranial nerve VII) inside the facial canal, at the level where the facial nerve exits the skull via the stylomastoid foramen, but exits through the petrotympanic fissure and descends in the infratemporal fossa. The chorda tympani is part of one of three cranial nerves that are involved in taste. The taste system involves a complicated feedback loop, with each nerve acting to inhibit the signals of other nerves. Structure The chorda tympani exits the cranial cavity through the internal acoustic meatus along with the facial nerve, then it travels through the middle ear, where it runs from posterior to anterior across the tympanic membrane. It passes between the malleus and the incus, on the medial surface of the neck of the malleus. The nerve continues through the petro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungiform Papilla
Lingual papillae (singular papilla) are small structures on the upper surface of the tongue that give it its characteristic rough texture. The four types of papillae on the human tongue have different structures and are accordingly classified as circumvallate (or vallate), fungiform, filiform, and foliate. All except the filiform papillae are associated with taste buds. Structure In living subjects, lingual papillae are more readily seen when the tongue is dry. There are four types of papillae present on the tongue: Filiform papillae Filiform papillae are the most numerous of the lingual papillae. They are fine, small, cone-shaped papillae covering most of the dorsum of the tongue. They are responsible for giving the tongue its texture and are responsible for the sensation of touch. Unlike the other kinds of papillae, filiform papillae do not contain taste buds. They cover most of the front two-thirds of the tongue's surface. They appear as very small, conical or cylindrical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phospholipase
A phospholipase is an enzyme that hydrolyzes phospholipids into fatty acids and other lipophilic substances. Acids trigger the release of bound calcium from cellular stores and the consequent increase in free cytosolic Ca2+, an essential step in calcium signaling to regulate intracellular processes. There are four major classes, termed A, B, C, and D, which are distinguished by the type of reaction which they catalyze: *Phospholipase A **Phospholipase A1 – cleaves the ''sn''-1 acyl chain (where ''sn'' refers to stereospecific numbering). **Phospholipase A2 – cleaves the ''sn''-2 acyl chain, releasing arachidonic acid. * Phospholipase B – cleaves both ''sn''-1 and ''sn''-2 acyl chains; this enzyme is also known as a lysophospholipase. *Phospholipase C – cleaves before the phosphate, releasing diacylglycerol and a phosphate-containing head group. PLCs play a central role in signal transduction, releasing the second messenger inositol triphosphate. * Phospholipase D †... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transient Receptor Potential
Transient receptor potential channels (TRP channels) are a group of ion channels located mostly on the plasma membrane of numerous animal cell types. Most of these are grouped into two broad groups: Group 1 includes TRPC ( "C" for canonical), TRPV ("V" for vanilloid), TRPVL ("VL" for vanilloid-like), TRPM ("M" for melastatin), TRPS ("S" for soromelastatin), TRPN ("N" for no mechanoreceptor potential C), and TRPA ("A" for ankyrin). Group 2 consists of TRPP ("P" for polycystic) and TRPML ("ML" for mucolipin). Other less-well categorized TRP channels exist, including yeast channels and a number of Group 1 and Group 2 channels present in non-animals. Many of these channels mediate a variety of sensations such as pain, temperature, different kinds of tastes, pressure, and vision. In the body, some TRP channels are thought to behave like microscopic thermometers and used in animals to sense hot or cold. Some TRP channels are activated by molecules found in spices like garlic (allicin) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphatidylinositol
Phosphatidylinositol (or Inositol Phospholipid) consists of a family of lipids as illustrated on the right, where red is x, blue is y, and black is z, in the context of independent variation, a class of the phosphatidylglycerides. In such molecules the isomer of the inositol group is assumed to be the myo- conformer unless otherwise stated. Typically phosphatidylinositols form a minor component on the cytosolic side of eukaryotic cell membranes. The phosphate group gives the molecules a negative charge at physiological pH. The form of phosphatidylinositol comprising the isomer ''muco''-inositol acts as a sensory receptor in the taste function of the sensory system. In this context it is often referred to as PtdIns, but that does not imply any molecular difference from phosphatidylinositols comprising the myo- conformers of inositol. The phosphatidylinositol can be phosphorylated to form phosphatidylinositol phosphate (PI-4-P, referred to as PIP in close context or inform ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
