QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online 5 October 2004
doi: 10.1242/jcs.01404

This Article Figures Only Full Text Full Text (PDF) All Versions of this Article: jcs.01404v1 117/22/5333    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Huff, T. Articles by Mannherz, H. G. Search for Related Content PubMed PubMed Citation Articles by Huff, T. Articles by Mannherz, H. G. Social Bookmarking                         What's this?

Nuclear localisation of the G-actin sequestering peptide thymosin ß₄

Thomas Huff^1,*, Olaf Rosorius¹, Angela M. Otto^1,, Christian S. G. Müller¹, Edda Ballweber², Ewald Hannappel¹ and Hans Georg Mannherz²

¹ Institut für Biochemie, Medizinische Fakultät, Universität Erlangen-Nürnberg, Fahrstr. 17, 91054 Erlangen, Germany
² Cytoskeletal Laboratory, Abteilung für Anatomie und Embryologie, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum, G ermany

^* Author for correspondence (e-mail: t.huff{at}biochem.uni-erlangen.de)

Accepted 8 July 2004

Thymosin ß₄ is regarded as the main G-actin sequestering peptide in the cytoplasm of mammalian cells. It is also thought to be involved in cellular events like cancerogenesis, apoptosis, angiogenesis, blood coagulation and wound healing. Thymosin ß₄ has been previously reported to localise intracellularly to the cytoplasm as detected by immunofluorescence. It can be selectively labelled at two of its glutamine-residues with fluorescent Oregon Green cadaverine using transglutaminase; however, this labelling does not interfere with its interaction with G-actin. Here we show that after microinjection into intact cells, fluorescently labelled thymosin ß₄ has a diffuse cytoplasmic and a pronounced nuclear staining. Enzymatic cleavage of fluorescently labelled thymosin ß₄ with AsnC-endoproteinase yielded two mono-labelled fragments of the peptide. After microinjection of these fragments, only the larger N-terminal fragment, containing the proposed actin-binding sequence exhibited nuclear localisation, whereas the smaller C-terminal fragment remained confined to the cytoplasm. We further showed that in digitonin permeabilised and extracted cells, fluorescent thymosin ß₄ was solely localised within the cytoplasm, whereas it was found concentrated within the cell nuclei after an additional Triton X100 extraction. Therefore, we conclude that thymosin ß₄ is specifically translocated into the cell nucleus by an active transport mechanism, requiring an unidentified soluble cytoplasmic factor. Our data furthermore suggest that this peptide may also serve as a G-actin sequestering peptide in the nucleus, although additional nuclear functions cannot be excluded.

Key words: ß-thymosins, Fluorescent labelling, Microinjection, Nuclear actin

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				Y. Yoo, X. Wu, and J.-L. Guan A Novel Role of the Actin-nucleating Arp2/3 Complex in the Regulation of RNA Polymerase II-dependent Transcription J. Biol. Chem., March 9, 2007; 282(10): 7616 - 7623. [Abstract] [Full Text] [PDF]

				D. McDonald, G. Carrero, C. Andrin, G. de Vries, and M. J. Hendzel Nucleoplasmic {beta}-actin exists in a dynamic equilibrium between low-mobility polymeric species and rapidly diffusing populations. J. Cell Biol., February 13, 2006; 172(4): 541 - 552. [Abstract] [Full Text] [PDF]

				T. Pederson and U. Aebi Nuclear Actin Extends, with No Contraction in Sight Mol. Biol. Cell, November 1, 2005; 16(11): 5055 - 5060. [Abstract] [Full Text] [PDF]

				B. J. Xu, Y. Shyr, X. Liang, L.-j. Ma, E. M. Donnert, J. D. Roberts, X. Zhang, V. Kon, N. J. Brown, R. M. Caprioli, et al. Proteomic Patterns and Prediction of Glomerulosclerosis and Its Mechanisms J. Am. Soc. Nephrol., October 1, 2005; 16(10): 2967 - 2975. [Abstract] [Full Text] [PDF]

				G. Sosne, P. L. Christopherson, R. P. Barrett, and R. Fridman Thymosin-{beta}4 Modulates Corneal Matrix Metalloproteinase Levels and Polymorphonuclear Cell Infiltration after Alkali Injury Invest. Ophthalmol. Vis. Sci., July 1, 2005; 46(7): 2388 - 2395. [Abstract] [Full Text] [PDF]