Actin-dependent activation of serum response factor in T cells by the viral oncoprotein tip

Cell Communication and Signaling

Research

Guido Posern¹  Jens-Christian Albrecht²  Kristin Katsch²  Sarah Jill de Jong²  Julia Steger²  Brigitte Biesinger²  Harald Genth³ 

[1] Department Molecular Biology, Max-Planck-Institut für Biochemie, Munich, Germany;Institut für Klinische und Molekulare Virologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany;Institut für Toxikologie, Medizinische Hochschule Hannover, Hannover, Germany;

关键词: Actin;    Herpesvirus saimiri;    Lck;    MRTF;    Oncoprotein;    Serum response factor;    T lymphocyte;   

DOI  :  10.1186/1478-811X-10-5

 received in 2012-01-20, accepted in 2012-03-03,  发布年份 2012

来源: Springer

【 摘 要 】

Serum response factor (SRF) acts as a multifunctional transcription factor regulated by mutually exclusive interactions with ternary complex factors (TCFs) or myocardin-related transcription factors (MRTFs). Binding of Rho- and actin-regulated MRTF:SRF complexes to target gene promoters requires an SRF-binding site only, whereas MAPK-regulated TCF:SRF complexes in addition rely on flanking sequences present in the serum response element (SRE). Here, we report on the activation of an SRE luciferase reporter by Tip, the viral oncoprotein essentially contributing to human T-cell transformation by Herpesvirus saimiri. SRE activation in Tip-expressing Jurkat T cells could not be attributed to triggering of the MAPK pathway. Therefore, we further analyzed the contribution of MRTF complexes. Indeed, Tip also activated a reporter construct responsive to MRTF:SRF. Activation of this reporter was abrogated by overexpression of a dominant negative mutant of the MRTF-family member MAL. Moreover, enrichment of monomeric actin suppressed the Tip-induced reporter activity. Further upstream, the Rho-family GTPase Rac, was found to be required for MRTF:SRF reporter activation by Tip. Initiation of this pathway was strictly dependent on Tip's ability to interact with Lck and on the activity of this Src-family kinase. Independent of Tip, T-cell stimulation orchestrates Src-family kinase, MAPK and actin pathways to induce SRF. These findings establish actin-regulated transcription in human T cells and suggest its role in viral oncogenesis.

【 授权许可】

Unknown   
© Katsch et al; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.