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Ptc1
Ptc1 is a type Two C phosphatase involved in the mating decision of yeast. Ptc1 competes with Fus3 for control of the 4 phosphorylation sites on the scaffold protein Ste5. Presence of the mating pheromone α-factor causes Ptc1 to be recruited to Ste5. This recruitment takes place via a 4 amino acid motif in the Ste5 phosphosites. Ptc1 is also involved in regulating the osmotic stress of yeast, especially via inactivation of Hog1, a member of the MAPK A mitogen-activated protein kinase (MAPK or MAP kinase) is a type of serine/threonine-specific protein kinases involved in directing cellular responses to a diverse array of stimuli, such as mitogens, osmotic stress, heat shock and proinflamm ... pathway. This inactivation occurred as a result of dephosphorylation of the phosphotheronine but not the phosphotyrosine residue in the phosphorylation lip of Hog1.{{cite journal , last=Warmka , first=Janel , date=Jan 2001 , title= Ptc1, a Type 2C Ser/Thr Phosphatase, Inactivates the H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mating Of Yeast
The mating of yeast, also known as yeast sexual reproduction, is a biological process that promotes genetic diversity and adaptation in yeast species. Yeast species, such as ''Saccharomyces cerevisiae'' (baker's yeast), are single-celled eukaryotes that can exist as either haploid cells, which contain a single set of chromosomes, or diploid cells, which contain two sets of chromosomes. Haploid yeast cells come in two mating types, a and α, each producing specific pheromones to identify and interact with the opposite type, thus displaying simple sexual differentiation. A yeast cell's mating type is determined by a specific genetic locus known as ''MAT'', which governs its mating behaviour. Haploid yeast can switch mating types through a form of genetic recombination, allowing them to change mating type as often as every cell cycle. When two haploid cells of opposite mating types encounter each other, they undergo a complex cell signaling, signaling process that leads to cell fusion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fus3
Fus3 is a MAPK protein involved in the mating decision of yeast. The dissociation of Fus3 from scaffold protein Ste5 results in the switch-like mating decision observed in yeast. During this process, Fus3 competes with a phosphatase Ptc1, attempting to phosphorylate 4 key phosphorylation sites on Ste5. When all 4 sites on Ste5 have been dephosphorylated by Ptc1, Fus3 dissociates from Ste5 and trans locates to the nucleus. One regulator of Fus3 is Ste5. Ste5 causes autophosphorylation of one of two locations modulated by the MAPK kinase Ste7 (the main activator of Fus3). This single phosphorylation causes Fus3 to phosphorylate Ste5 leading to a decrease in signal. However, Ste5 also selectively catalytically unlocks Fus3 for phosphorylation by Ste7. Both the catalytic domain on Ste5 as well as Ste7 must be present in order to activate Fus3, which helps to explain why Fus3 is only activated during the mating pathway, and remains inactive in other situations which use Ste7. When b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ste5
Ste5 is a Mitogen-activated protein kinases, MAPK scaffold protein involved in the mating of yeast. The active complex is formed by interactions with the MAPK Fus3, the Mitogen-activated protein kinase kinase, MAPK kinase (MAPKK) Ste7, and the MAP kinase kinase kinase, MAPKK kinase Ste11. After the induction of mating by an appropriate mating pheromone (either a-factor or α –factor) Ste5 and its associated proteins are recruited to the Cell Membrane, membrane. Ste4 helps to recruit Ste5 but is not required for the attachment of Ste5 to the membrane, which depends on a pleckstrin homology domain as well as an Amphiphile, amphipathic alpha-helical domain in the amino terminus. During mating, Fus3 MAPK and Ptc1 phosphatase compete to control 4 phosphorylation sites on the Ste5 scaffold. When all of 4 sites have been dephosphorylated by Ptc1, Fus3 is released and becomes active. Ste5 plays 2 main roles in the mating signal pathway: #Binds the components of the MAPK cascade and hold ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphatase
In biochemistry, a phosphatase is an enzyme that uses water to cleave a phosphoric acid Ester, monoester into a phosphate ion and an Alcohol (chemistry), alcohol. Because a phosphatase enzyme catalysis, catalyzes the hydrolysis of its Substrate (chemistry), substrate, it is a subcategory of hydrolases. Phosphatase enzymes are essential to many biological functions, because phosphorylation (e.g. by protein kinases) and dephosphorylation (by phosphatases) serve diverse roles in cell growth, cellular regulation and cell signaling, signaling. Whereas phosphatases remove phosphate groups from molecules, kinases catalyze the transfer of phosphate groups to molecules from Adenosine triphosphate, ATP. Together, kinases and phosphatases direct a form of post-translational modification that is essential to the cell's regulatory network. Phosphatase enzymes are not to be confused with phosphorylase enzymes, which catalyze the transfer of a phosphate group from hydrogen phosphate to an acce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scaffold Protein
In biology, scaffold proteins are crucial regulators of many key signalling pathways. Although scaffolds are not strictly defined in function, they are known to interact and/or bind with multiple members of a signalling pathway, tethering them into complexes. In such pathways, they regulate signal transduction and help localize pathway components (organized in complexes) to specific areas of the cell such as the plasma membrane, the cytoplasm, the nucleus, the Golgi, endosomes, and the mitochondria. History The first signaling scaffold protein discovered was the Ste5 protein from the yeast ''Saccharomyces cerevisiae''. Three distinct domains of Ste5 were shown to associate with the protein kinases Ste11, Ste7, and Fus3 to form a multikinase complex. Function Scaffold proteins act in at least four ways: tethering signaling components, localizing these components to specific areas of the cell, regulating signal transduction by coordinating positive and negative feedback s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pheromone
A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavior of the receiving individuals. There are ''alarm signal, alarm pheromones'', ''food trail pheromones'', ''sex pheromones'', and many others that affect behavior or physiology. Pheromones are used by many organisms, from basic unicellular prokaryotes to complex multicellular eukaryotes. Their use among insects has been particularly well documented. In addition, some vertebrates, plants and ciliates communicate by using pheromones. The ecological functions and evolution of pheromones are a major topic of research in the field of chemical ecology. Background The portmanteau word "pheromone" was coined by Peter Karlson and Martin Lüscher in 1959, based on the Greek language, Greek () and (). Pheromones are also sometimes classified as ec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitogen-activated Protein Kinases
A mitogen-activated protein kinase (MAPK or MAP kinase) is a type of serine/threonine-specific protein kinases involved in directing cellular responses to a diverse array of stimuli, such as mitogens, osmotic stress, heat shock and proinflammatory cytokines. They regulate cell functions including proliferation, gene expression, differentiation, mitosis, cell survival, and apoptosis. MAP kinases are found in eukaryotes only, but they are fairly diverse and encountered in all animals, fungi and plants, and even in an array of unicellular eukaryotes. MAPKs belong to the CMGC (CDK/MAPK/GSK3/CLK) kinase group. The closest relatives of MAPKs are the cyclin-dependent kinases (CDKs). Discovery The first mitogen-activated protein kinase to be discovered was ERK1 (MAPK3) in mammals. Since ERK1 and its close relative ERK2 (MAPK1) are both involved in growth factor signaling, the family was termed "mitogen-activated". With the discovery of other members, even from distant organisms (e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
