Nuclear calmodulin/62 kDa calmodulin-binding protein complexes in interphasic and mitotic cells.
J Cell Sci
; 107 ( Pt 12): 3601-14, 1994 Dec.
Article
em En
| MEDLINE
| ID: mdl-7706409
ABSTRACT
We report here that a 62 kDa calmodulin-binding protein (p62), recently identified in the nucleus of rat hepatocytes, neurons and glial cells, consists of four polypeptides showing pI values between 5.9 and 6.1. By using a DNA-binding overlay assay we found that the two most basic of the p62 polypeptides bind both single- and double-stranded DNA. The intranuclear distribution of calmodulin and p62 was analysed in hepatocytes and astrocyte precursor cells, and in proliferating and differentiated astrocytes in primary cultures by immunogold-labeling methods. In non-dividing cells nuclear calmodulin was mostly localized in heterochromatin although it was also present in euchromatin and nucleoli. A similar pattern was observed for p62, with the difference that it was not located in nucleoli. p62/calmodulin complexes, mainly located over heterochromatin domains were also observed in interphasic cells. These complexes remained associated with the nuclear matrix after in situ sequential extraction with nucleases and high-salt containing buffers. In dividing cells, both calmodulin and p62 were found distributed over all the mitotic chromosomes but the p62/calmodulin aggregates were disrupted. These results suggest a role for calmodulin and p62 in the condensation of the chromatin.
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Base de dados:
MEDLINE
Assunto principal:
Proteínas de Ligação a Calmodulina
/
Calmodulina
/
Ciclo Celular
/
Núcleo Celular
/
Proteínas de Ligação a DNA
Idioma:
En
Ano de publicação:
1994
Tipo de documento:
Article