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001-es BibID:	BIBFORM029040
Első szerző:	Erdődi Ferenc (biokémikus)
Cím:	Purification and characterization of three distinct types of protein phosphatase catalytic subunits in bovine platelets / Ferenc Erdődi, Csilla Csortos, Lloyd Sparks, Andrea Murányi, Pál Gergely
Dátum:	1992
ISSN:	0003-9861
Megjegyzések:	The catalytic subunits of bovine platelet protein phosphatases were separated into three distinct forms by chromatography on heparin-Sepharose. Each phosphatase was further purified to apparent homogeneity as judged in sodium dodecyl sulfate-polyacrylamide gel yielding single protein bands of 37, 41, and 36 kDa. The 37-kDa phosphatase was excluded from heparin-Sepharose and preferentially dephosphorylated the alpha-subunit of phosphorylase kinase. It was stimulated by polycations (polybrene or histone H1) and was inhibited by okadaic acid (IC50 = 0.3 nM), but its activity was not influenced by inhibitor-2 or heparin. The 41-kDa phosphatase was eluted from heparin-Sepharose by 0.20-0.25 M NaCl and preferentially dephosphorylated the beta-subunit of phosphorylase kinase. It was stimulated by polycations and inhibited by okadaic acid (IC50 = 2 nM), but its activity was not affected by inhibitor-2 or heparin. The 36-kDa phosphatase was eluted from heparin-Sepharose by 0.45-0.50 M NaCl and preferentially dephosphorylated the beta-subunit of phosphorylase kinase. It was inhibited by inhibitor-2, heparin, histone H1, and okadaic acid (IC50 = 70 nM). The 37- and 36-kDa phosphatases can be classified as type-2A and type-1 enzymes, respectively. The 41-kDa phosphatase does not precisely fit the criteria of either type, showing only partial similarities to both type-1 and type-2A enzymes and it may represent a novel type of protein phosphatase in bovine platelets.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban egyetemen (Magyarországon) készült közlemény
Megjelenés:	Archives of Biochemistry And Biophysics. - 298 : 2 (1992), p. 682-687. -
További szerzők:	Sparks, Lloyd Csortos Csilla (1956-) (biokémikus) Gergely Pál (1947-) (biokémikus) Murányi Andrea (1966-) (biokémikus)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM028726
Első szerző:	Kiss Enikő
Cím:	Integrin-linked kinase phosphorylates the myosin phosphatase target subunit at the inhibitory site in platelet cytoskeleton / Enikő Kiss, Andrea Murányi, Csilla Csortos, Pál Gergely, Masaaki Ito, David J. Hartshorne, Ferenc Erdődi
Dátum:	2002
ISSN:	0264-6021
Megjegyzések:	The myosin phosphatase (MP) composed of the catalytic subunit of type 1 protein phosphatase and myosin phosphatase target subunit isoform 1 (MYPT1) was identified as the major serine/threonine phosphatase component in the platelet-cytoskeleton fraction. MYPT1 was phosphorylated by cytoskeletal kinase(s), but the identity of the kinase(s) and the effect of phosphorylation were not established. Incubation of platelet-cytoskeletal fraction with MgATP or MgATP[S] (magnesium adenosine 5'-[gamma-thio]triphosphate) caused a decrease in the 20 kDa light-chain of smooth-muscle myosin (MLC20) phosphatase and phosphorylase phosphatase activities. MYPT1 contains a phosphorylation site, Thr-695, involved in the inhibition of MP in a RhoA/Rho kinase-dependent manner. The cytoskeletal kinase(s) phosphorylated Thr-695 of glutathione S-transferase (GST)-MYPT1, as determined with an antibody specific for phosphorylated Thr-695. The level of Rho kinase was low in the cytoskeletal fraction and was detected primarily in the membrane and cytosolic fractions. The phosphorylation of Thr-695 by the cytoskeletal kinase(s) was not affected by Rho kinase inhibitor, Y-27632, suggesting that kinase(s) other than Rho kinase were involved. In-gel kinase assay identified a kinase at 54-59 kDa that phosphorylated the C-terminal fragment of MYPT1 (GST-MYPT1(667-1004)). Western blots detected both zipper-interacting protein kinase (ZIPK) and integrin-linked kinase (ILK) at 54-59 kDa in the cytoskeleton and membrane fractions. Cytoskeletal ZIPK and ILK were separated and partially purified by chromatography on SP-Sepharose and on MonoQ. ZIPK preferentially phosphorylated MLC20 and had low activity on MYPT1. ILK phosphorylated both MLC20 and MYPT1 and phosphorylation of MYPT1 occured on Thr-695. The above results raise the potential for regulation of MP activity in platelet cytoskeleton by ILK and suggest an alternative to the Rho-linked pathway.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban egyetemen (Magyarországon) készült közlemény
Megjelenés:	Biochemical Journal. - 365 : 1 (2002), p. 79-87. -
További szerzők:	Murányi Andrea (1966-) (biokémikus) Ito, Masaaki Hartshorne, David J. Erdődi Ferenc (1953-) (biokémikus) Csortos Csilla (1956-) (biokémikus) Gergely Pál (1947-) (biokémikus)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
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