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Titolo:
PROTEIN PHOSPHATASES MAINTAIN THE ORGANIZATION AND STRUCTURAL INTERACTIONS OF HEPATIC KERATIN INTERMEDIATE FILAMENTS
Autore:
TOIVOLA DM; GOLDMAN RD; GARROD DR; ERIKSSON JE;
Indirizzi:
TURKU CTR BIOTECHNOL,BIOCITY,POB 123 FIN-20521 TURKU FINLAND TURKU CTR BIOTECHNOL FIN-20521 TURKU FINLAND ABO AKAD UNIV,DEPT BIOL FIN-20520 TURKU FINLAND NORTHWESTERN UNIV,SCH MED,DEPT CELL & MOL BIOL CHICAGO IL 60611 UNIV MANCHESTER,SCH BIOL SCI MANCHESTER M13 9PT LANCS ENGLAND
Titolo Testata:
Journal of Cell Science
, volume: 110, anno: 1997,
parte:, 1
pagine: 23 - 33
SICI:
0021-9533(1997)110:<23:PPMTOA>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACTIN MICROFILAMENT INTEGRITY; ISOLATED RAT HEPATOCYTES; INHIBITORS OKADAIC ACID; LIVING NONMUSCLE CELLS; CYCLIC PEPTIDE TOXIN; MICROCYSTIN-LR; CALYCULIN-A; EPITHELIAL DESMOSOMES; DIHYDROMICROCYSTIN-LR; HEPATOCELLULAR UPTAKE;
Keywords:
PROTEIN PHOSPHORYLATION; MICROCYSTIN-LR; MICROFILAMENT; INTERMEDIATE FILAMENT; KERATIN; DESMOSOME; DESMOPLAKIN; CA2+/CALMODULIN-DEPENDENT PROTEIN KINASE; CAMP-DEPENDENT PROTEIN KINASE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
64
Recensione:
Indirizzi per estratti:
Citazione:
D.M. Toivola et al., "PROTEIN PHOSPHATASES MAINTAIN THE ORGANIZATION AND STRUCTURAL INTERACTIONS OF HEPATIC KERATIN INTERMEDIATE FILAMENTS", Journal of Cell Science, 110, 1997, pp. 23-33

Abstract

The importance of protein phosphatases in the maintenance of cytoskeletal structure is supported by the serious liver injury caused by microcystin-LR, a hepatotoxic inhibitor of type-1 and type-2A serine/threonine protein phosphatases. We used the microcystin-LR-induced cell injury as a model to study the roles of protein dephosphorylation in maintaining cytoskeletal structure and cellular interactions in primary rat hepatocyte cultures. Confocal microscopy revealed that the first visible effect of microcystin-LR is disruption of desmoplakin organization at the cell surface, indicating dissociation of desmosomes. This effect is followed by a dramatic reorganization of both the intermediate filament (keratins 8 and 18) and microfilament networks, resulting in a merged structure in which the intermediate filaments are organized around condensed actin core. Keratin 8, keratin 18 and desmoplakin I/IIare the major cytoskeleton-associated targets for microcystin-LR-induced phosphorylation. Hyperphosphorylation of keratin 8 and 18 is accompanied by an increased keratin solubility, which correlates with the observed morphological effects, Phosphopeptide mapping shows that four specific tryptic phosphopeptides are highly phosphorylated predominantly in the soluble pool of keratin 18, whereas keratin 8 shows no indications of such assembly state-specific sites. Phosphopeptide maps of keratins phosphorylated in vivo and in vitro indicate that Ca2+/calmodulin-dependent kinase may be involved in regulating the serine-specificphosphorylation of both keratin 8 and keratin 18, while cAMP-dependent protein kinase does not seem to play a major role in this context, Taken together, our results show that the interactions between keratin intermediate filaments and desmosomes as well as the assembly states of their main constituent proteins, are directly regulated by serine/threonine kinase/phosphatase equilibria.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 14:46:02