Role of Ca2+ Activation and Bilobal Structure of Calmodulin in Nuclear and Nucleolar Localization.
From: Division of Basic Medical Sciences, St George’s University of London, London SW17 0RE, UK.
The Biochemical journal
- Publish Date: Feb 2007
- ISSN: 1470-8728
- Volume: 402
- Issue: 1
- Pages: 71-80
- Medium: Internet
- Language: English
- Citation (JAMA): Thorogate Richard, Török Katalin, et al. Role of Ca2+ Activation and Bilobal Structure of Calmodulin in Nuclear and Nucleolar Localization.. Biochem. J. Feb 2007;402:71-80
Abstract
Ca2+ signalling to the nucleus is thought to occur by calmodulin entry into the nucleus where calmodulin has many functions. In the present study we have investigated the role of Ca2+ and the N- and C-terminal lobes of calmodulin in its subnuclear targeting by using fluorescently labelled calmodulin and its mutants and confocal microscopy. Our data show, first, that Ca2+ stimulation induces a reorganization of subnuclear structures to which apo-calmodulin can bind. Secondly, Ca2+-independent association of the C-terminal lobe is seen with subnuclear structures such as chromatin, the nuclear envelope and the nucleoli. Thirdly, Ca2+-dependent accumulation of both calmodulin and the C-terminal calmodulin lobe occurs in the nucleoli. The N-terminal lobe of calmodulin does not show significant binding to subnuclear structures although, similarly to the C-terminal lobe, it accumulates in the nucleoplasm of wheat germ agglutinin-blocked nuclei suggesting that a facilitated nuclear export mechanism exists for calmodulin.
Mesh Headings (Keywords): Active Transport, Cell Nucleus, Binding Sites, Calcium, Calmodulin, Cell Nucleolus, Cell Nucleus, Fluorescent Dyes, Hela Cells, Humans, Microscopy, Confocal, Rhodamines
Check for Full Text / PubMed Unique Identifier (PMID): 17040208
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