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001-es BibID:	BIBFORM063541
Első szerző:	Csortos Csilla (biokémikus)
Cím:	Structural comparison of the B and B' subunits of protein phosphatase 2A / Cs. Csortos, S. Zolnierowicz, S. Durbin, A. A. DePaoli-Roach
Dátum:	1993
ISSN:	0892-6638
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idézhető absztrakt
Megjelenés:	Faseb Journal 7 : 7 (1993), p. 1156. -
További szerzők:	Zolnierowicz, Stanislaw Durbin, Steve D. DePaoli-Roach, Anna A.
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM047047
035-os BibID:	PMID:8576224
Első szerző:	Csortos Csilla (biokémikus)
Cím:	High complexity in the expression of the B' subunit of protein phosphatase 2A0. Evidence for the existence of at least seven novel isoforms / Csilla Csortos, Stanislaw Zolnierowicz, Éva Bakó, Stephen D. Durbin, Anna A. DePaoli-Roach
Dátum:	1996
ISSN:	0021-9258 1083-351X
Megjegyzések:	Association of the catalytic subunit (C2) with a variety of regulatory subunits is believed to modulate the activity and specificity of protein phosphatase 2A (PP2A). In this study we report the cloning and expression of a new family of B-subunit, the B', associated with the PP2A0 form. Polymerase chain reactions and cDNA library screening have identified at least seven cDNA isotypes, designated alpha, beta 1, beta 2, beta 3, beta 4, gamma, and delta. The different beta subtypes appear to be generated by alternative splicing. The deduced amino acid sequences of the alpha, beta 2, beta 3, beta 4 and gamma isoforms predict molecular weights of 57,600, 56,500, 60,900, 52,500, and 68,000, respectively. The proteins are 60-80% identical and differ mostly at their termini. Two of the isoforms, B' beta 3 and B' gamma, contain a bipartite nuclear localization signal in their COOH terminus. No homology was found with other B- or B- related subunits. Northern analyses indicate a tissue-specific expression of the isoforms. Expression of B' alpha protein in Escherichia coli generated a polypeptide of approximately 53 kDa, similar to the size of the B' subunit present in the purified PP2A0. The recombinant protein was recognized by antibody raised against native B' and interacted with the dimeric PP2A (A.C2) to generate a trimeric phosphatase. The deduced amino acid sequences of the B' isoforms show significant homology to mammalian, fungal, and plant nucleotide sequences of unknown function present in the data bases. Notably, a high degree of homology (55-66%) was found with a yeast gene, RTS1, encoding a multicopy suppressor of a rox3 mutant. Our data indicate that at least seven B' subunit isoforms may participate in the generation of a large number of PP2A0 holoenzymes that may be spatially and/or functionally targeted to different cellular processes.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Journal of Biological Chemistry. - 271 : 5 (1996), p. 2578-2588. -
További szerzők:	Zolnierowicz, Stanislaw Bakó Éva (1958-) (biokémikus) Durbin, Steve D. DePaoli-Roach, Anna A.
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM047050
035-os BibID:	PMID:7942275
Első szerző:	DePaoli-Roach, Anna A.
Cím:	Serine/threonine protein phosphatases in the control of cell function / Anna A. DePaoli-Roach, In-Kyung Park, Vaclav Cerovsky, Csilla Csortos, Stephen D. Durbin, Martha J. Kuntz, Albert Sitikov, Pauline M. Tang, Alexander Verin, Stanislaw Zolnierowicz
Dátum:	1994
Megjegyzések:	Reversible protein phosphorylation is a fundamental mechanism by which many biological functions are regulated. Achievement of such control requires the coordinated action of the interconverting enzymes, the protein kinases and protein phosphatases. By comparison with protein kinases, a limited number of protein phosphatase catalytic subunits are present in the cell, which raises the question of how such a small number of dephosphorylating enzymes can counterbalance the action of the more numerous protein kinases. In mammalian cells, four major classes of Ser/Thr-specific phosphatase catalytic subunits have been identified, comprising two distinct gene families. The high degree of homology among members of the same family, PP1, PP2A and PP2B, and the high degree of evolutionary conservation between organisms as divergent as mammals and yeast, implies that these enzymes are involved in fundamental cell functions. Type 1 enzymes appear to acquire specificity by association with targeting regulatory subunits which direct the enzymes to specific cellular compartments, confer substrate specificity and control enzyme activity. In spite of the progress made in determining the structure of the PP2A subunits, very little is known about the control of this activity and about substrate selection. Recent studies have unravelled a significant number of regulatory subunits. The potential existence of five distinct B or B-related polypeptides, some of which are present in multiple isoforms, two A and two C subunit isoforms, raises the possibility that a combinatorial association could generate a large number of specific PP2A forms with different substrate specificity and/or cellular localization. Moreover, biochemical, biological and genetic studies all concur in suggesting that the regulatory subunits may play an important role in determining the properties of the Ser/Thr protein phosphatases and hence their physiological functions.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Advances in Enzyme Regulation. - 34 (1994), p. 199-224. -
További szerzők:	Park, In-Kyung Cerovsky, Vaclav Csortos Csilla (1956-) (biokémikus) Durbin, Steve D. Kuntz, Martha J. Sitikov, Albert Tang, Pauline M. Verin, Alexander Zolnierowicz, Stanislaw
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM047049
035-os BibID:	PMID:7918404
Első szerző:	Zolnierowicz, Stanislaw
Cím:	Diversity in the regulatory B-subunits of protein phosphatase 2A: identification of a novel isoform highly expressed in brain / Stanislaw Zolnierowicz, Csilla Csortos, Jeffry Bondor, Alexander Verin, Marc C. Mumby, Anna A. DePaoli-Roach
Dátum:	1994
ISSN:	0006-2960
Megjegyzések:	The physiological role of type 2A protein phosphatases (PP2A) is dependent upon the association of the catalytic subunit with a variety of regulatory subunits. In order to understand the function of PP2A, we have undertaken purification of the holoenzymes and molecular cloning of the regulatory subunits. Two trimeric forms containing distinct B-subunits, PP2A0 and PP2A1, have been purified from rabbit skeletal muscle. The B-subunits associated with PP2A0 and PP2A1 migrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with slightly different mobility, approximately 52.5 and approximately 51.5 kDa, respectively and showed distinct immunological properties. The B' form of B-subunit associated with PP2A0 was recognized by antibodies against the B-subunit present in bovine heart PP2A but not by antibodies specific to the B subunit isoforms of rabbit PP2A1. Cloning of cDNAs encoding the B subunit of PP2A1 resulted in the isolation of a cDNA highly homologous to, but distinct from, the B alpha subunit isoform. The deduced amino acid sequence of this novel isoform, which was designated B gamma, encoded a protein which was 81% and 87% identical to the B alpha and B beta isoforms, respectively. Northern blot analysis indicated that the B gamma isoform is highly expressed in rabbit brain as a transcript of 3.9 kb. Analysis of B-subunit expression by Western blot indicated a general parallel with the message levels. In conclusion, our data reveal even greater complexity of PP2A trimeric holoenzymes due to the identification of a novel B regulatory subunit isoform of PP2A1 and a distinct B' subunit associated with PP2A0.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Biochemistry. - 33 : 39 (1994), p. 11858-11867. -
További szerzők:	Csortos Csilla (1956-) (biokémikus) Bondor, Jeffry Verin, Alexander Mumby, Marc C. DePaoli-Roach, Anna A.
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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