von Dr. Diana Sandulache
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| [1.] Dsa/Fragment 020 01 - Diskussion Zuletzt bearbeitet: 2016-08-02 19:24:22 WiseWoman | Dsa, Fragment, Gesichtet, KomplettPlagiat, SMWFragment, Schutzlevel sysop, Wikipedia Serine-threonine-specific protein kinase 2006 |
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| Untersuchte Arbeit: Seite: 20, Zeilen: 1-13 |
Quelle: Wikipedia Serine-threonine-specific protein kinase 2006 Seite(n): 1 (online source), Zeilen: - |
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| Structure and autoregulation
The CaM kinases consist of an N-terminal catalytic domain, a regulatory domain and an associative domain. In the absence of Ca2+/calmodulin, the catalytic domain is auto inhibited by the regulatory domain, which contains a pseudo substrate sequence. Several CaM kinases aggregate into a homo-oligomer or hetero-oligomer. Upon activation by Ca2+/calmodulin, the activated CaM kinases autophosphorylate each other, in an intermolecular reaction. This has two effects: • An increase in affinity for the calmodulin complex, prolonging the time the kinase is active. • Continued activation of the phosphorylated kinase complex even after the calmodulin complex has dissociated from the kinase complex, which prolongs the active state even more. |
Structure and autoregulation
The CaM kinases consist of an N-terminal catalytic domain, a regulatory domain, and an association domain. In the absence of Ca2+/calmodulin, the catalytic domain is autoinhibited by the regulatory domain, which contains a pseudosubstrate sequence. Several CaM kinases aggregate into a homooligomer or heterooligomer. Upon activation by Ca2+/calmodulin, the activated CaM kinases autophosphorylate each other in an intermolecular reaction. This has two effects: 1. An increase in affinity for the calmodulin complex, prolonging the time the kinase is active. 2. Continued activation of the phosphorylated kinase complex even after the calmodulin complex has dissociated from the kinase complex, which prolongs the active state even more. |
No source is given. |
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| [2.] Dsa/Fragment 020 14 - Diskussion Zuletzt bearbeitet: 2016-08-02 13:08:09 WiseWoman | Dsa, Fragment, Gesichtet, KomplettPlagiat, SMWFragment, Schutzlevel sysop, Wikipedia Protein kinase 2007 |
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| Untersuchte Arbeit: Seite: 20, Zeilen: 14-40 |
Quelle: Wikipedia Protein kinase 2007 Seite(n): 1 (online source), Zeilen: - |
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| 2) Tyrosine-specific protein kinases
Tyrosine-specific protein kinases phosphorylate tyrosine amino acid residues, and are, like serine/threonine-specific kinases, used in signal transduction. They act primarily as growth factor receptors and in downstream signaling from growth factors; some examples: • Platelet-derived growth factor (PDGF) receptor; • Epidermal growth factor (EGF) receptor; • Insulin receptor and insulin-like growth factor (IGF1) receptor; • Stem cell factor (scf) receptor (also called c-kit). - Receptor tyrosine kinases: These kinases consist of a transmembrane receptor with a tyrosine kinase domain protruding into the cytoplasm. They play an important role in regulating cell division, cellular differentiation, and morphogenesis. More than 50 receptor tyrosine kinases are known in mammals. Structure The extracellular domain serves as the ligand-binding part of the molecule. It can be a separate unit that is attached to the rest of the receptor by a disulfide bond. The same mechanism can be used to bind two receptors together to form a homo- or heterodimer. The transmembrane element is a single α helix. The intracellular or cytoplasmic domain is responsible for the (highly conserved) kinase activity, as well as several regulatory functions. Regulation Ligand binding causes two reactions: • dimerization of two monomeric receptor kinases or • stabilization of a loose dimer. Many ligands of receptor tyrosine kinases are multivalent. Some tyrosine receptor kinases (e.g., the platelet-derived growth factor receptor) can form heterodimers with other similar but not identical kinases of the same subfamily, allowing a highly varied response to the extracellular signal. |
Tyrosine-specific protein kinases
[...] Tyrosine-specific protein kinases (EC 2.7.10.1) phosphorylate tyrosine amino acid residues, and are, like serine/threonine-specific kinases, used in signal transduction. They act primarily as growth factor receptors and in downstream signaling from growth factors; some examples: • Platelet-derived growth factor (PDGF) receptor; • Epidermal growth factor (EGF) receptor; • Insulin receptor and insulin-like growth factor (IGF1) receptor; • Stem cell factor (scf) receptor (also called c-kit, see the article on gastrointestinal stromal tumor). Receptor tyrosine kinases These kinases consist of a transmembrane receptor with a tyrosine kinase domain protruding into the cytoplasm. They play an important role in regulating cell division, cellular differentiation, and morphogenesis. More than 50 receptor tyrosine kinases are known in mammals. Structure The extracellular domain serves as the ligand-binding part of the molecule. It can be a separate unit that is attached to the rest of the receptor by a disulfide bond. The same mechanism can be used to bind two receptors together to form a homo- or heterodimer. The transmembrane element is a single α helix. The intracellular or cytoplasmic domain is responsible for the (highly conserved) kinase activity, as well as several regulatory functions. Regulation Ligand binding causes two reactions: 1. Dimerization of two monomeric receptor kinases or stabilization of a loose dimer. Many ligands of receptor tyrosine kinases are multivalent. Some tyrosine receptor kinases (e.g., the platelet-derived growth factor receptor) can form heterodimers with other similar but not identical kinases of the same subfamily, allowing a highly varied response to the extracellular signal. |
No source is given. The bullet points under Regulation are misleading, as the two reactions are the one on the bottom of page 20 and the one on the top of page 21. |
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