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J Cell Biochem. 2015 Dec;116(12):2755-65. doi: 10.1002/jcb.25218.

Localization of α-Dystrobrevin in Cajal Bodies and Nucleoli: A New Role for α-Dystrobrevin in the Structure/Stability of the Nucleolus.

Author information

1
Departamento de Gen, é, tica y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV- IPN), Mexico City, Mexico.
2
Departamento de Ciencias de la Vida, Carrera de Ingeniería en Biotecnología, Universidad de las Fuerzas Armadas-ESPE, Sangolquí, Ecuador.

Abstract

α-Dystrobrevin (α-DB) is a cytoplasmic component of the dystrophin-associated complex involved in cell signaling; however, its recently revealed nuclear localization implies a role for this protein in the nucleus. Consistent with this, we demonstrated, in a previous work that α-DB1 isoform associates with the nuclear lamin to maintain nuclei morphology. In this study, we show the distribution of the α-DB2 isoform in different subnuclear compartments of N1E115 neuronal cells, including nucleoli and Cajal bodies, where it colocalizes with B23/nucleophosmin and Nopp140 and with coilin, respectively. Recovery in a pure nucleoli fraction undoubtedly confirms the presence of α-DB2 in the nucleolus. α-DB2 redistributes in a similar fashion to that of fibrillarin and Nopp140 upon actinomycin-mediated disruption of nucleoli and to that of coilin after disorganization of Cajal bodies through ultraviolet-irradiation, with relocalization of the proteins to the corresponding reassembled structures after cessation of the insults, which implies α-DB2 in the plasticity of these nuclear bodies. That localization of α-DB2 in the nucleolus is physiologically relevant is demonstrated by the fact that downregulation of α-DB2 resulted in both altered nucleoli structure and decreased levels of B23/nucleophosmin, fibrillarin, and Nopp140. Since α-DB2 interacts with B23/nucleophosmin and overexpression of the latter protein favors nucleolar accumulation of α-DB2, it appears that targeting of α-DB2 to the nucleolus is dependent on B23/nucleophosmin. In conclusion, we show for the first time localization of α-DB2 in nucleoli and Cajal bodies and provide evidence that α-DB2 is involved in the structure of nucleoli and might modulate nucleolar functions.

KEYWORDS:

B23/NUCLEOPHOSMIN; CAJAL BODIES; COILIN; FIBRILLARIN; N1E115 NEURONAL CELLS; NUCLEAR BODIES; NUCLEOLUS; α-DYSTROBREVIN

PMID:
25959029
DOI:
10.1002/jcb.25218
[Indexed for MEDLINE]

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