Mechanism of localization of betaII-tubulin in the nuclei of cultured rat kidney mesangial cells.
Cell Motil Cytoskeleton
; 49(4): 208-17, 2001 Aug.
Article
en En
| MEDLINE
| ID: mdl-11746665
ABSTRACT
Tubulin is an alphabeta heterodimer. Both the alpha and beta polypeptides exist as multiple isotypes. Although tubulin was generally thought to exist only in the cytoplasm, we have previously reported the presence of the betaII isotype of tubulin in the nuclei of cultured rat kidney mesangial cells, smooth-muscle-like cells that reside in the glomerular mesangium; nuclear betaII exists as an alphabetaII dimer, capable of binding to colchicine, but in non-microtubule form [Walss et al., 1999 Cell Motil. Cytoskeleton 42274-284]. We have now investigated the nature of the process by which alphabetaII enters the nuclei of these cells. By micro-injecting fluorescently labeled alphabetaII into mesangial cells, we found that alphabetaII was present in the nuclei of cells only if they were allowed to go through mitosis. In contrast, there were no circumstances in which microinjected fluorescently labeled abetaII or alphabetaIV dimers entered the nuclei. These findings, together with the absence of any nuclear localization signal in alphabetaII, strongly favor the model that alphabetaII, rather than being transported into the intact nucleus, co-assembles with the nucleus at the end of mitosis. Our results also indicate that the nuclear localization mechanism is specific for alphabetaII. This result raises the possibility that alphabetaII may have a specific function that requires its presence in the nuclei of cultured rat kidney mesangial cells.
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Colección:
01-internacional
Base de datos:
MEDLINE
Contexto en salud:
6_ODS3_enfermedades_notrasmisibles
Problema de salud:
6_kidney_renal_pelvis_ureter_cancer
Asunto principal:
Núcleo Celular
/
Mesangio Glomerular
/
Microtúbulos
Tipo de estudio:
Diagnostic_studies
/
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Cell Motil Cytoskeleton
Año:
2001
Tipo del documento:
Article
País de afiliación:
Estados Unidos