JBC

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Morgavi, P.
Right arrow Articles by Rubartelli, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Morgavi, P.
Right arrow Articles by Rubartelli, A.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

Volume 272, Number 17, Issue of April 25, 1997 pp. 11256-11260
©1997 by The American Society for Biochemistry and Molecular Biology, Inc.

The Association of HIV-1 Tat with Nuclei Is Regulated by Ca2+ Ions and Cytosolic Factors

(Received for publication, January 31, 1997)

Paola Morgavi Dagger , Neris Bonifaci Dagger , Massimiliano Pagani , Sara Costigliolo Dagger , Roberto Sitia and Anna Rubartelli Dagger

From the Dagger  National Institute of Cancer Research, 16132 Genova and  DIBIT-San Raffaele Scientific Institute, 20132 Milano, Italy

Human immunodeficiency virus-1 (HIV-1) Tat, a nuclear transcription factor, has been shown to function extracellularly, implying that some Tat molecules escape nuclear import and are secreted. This raises the question of what regulates, in HIV-1-infected cells, the nuclear targeting of the polypeptide. Here we show that cytosolic components activated by Ca2+ ions are required to reveal the karyophilic properties of Tat: in vitro translated Tat molecules do not associate with isolated nuclei unless preincubated with Ca2+. Moreover, Ca2+ ions induce karyophilicity of chemically synthesized Tat molecules only upon addition of cytosolic extracts. The Ca2+-induced karyophilicity is prevented by inhibitors of either tyrosine kinases (herbimycin A and genistein) or tyrosine phosphatases (vanadate), suggesting the involvement of Ca2+-dependent phosphorylation/dephosphorylation events. In line with these observations, the transcriptional activity of Tat is inhibited by treatment with either vanadate or genistein. The same occurs with Tat mutants lacking either one or both the two tyrosine residues (positions 26 and 47). Hence, Ca2+-dependent tyrosine kinase(s) and phosphatase(s) act on accessory cellular protein(s), which in turn are responsible of Tat karyophilicity.


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


This article has been cited by other articles:


Home page
 J. Immunol.Home page
M. R. Zocchi, A. Rubartelli, P. Morgavi, and A. Poggi
HIV-1 Tat Inhibits Human Natural Killer Cell Function by Blocking L-Type Calcium Channels
J. Immunol., September 15, 1998; 161(6): 2938 - 2943.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
A. Poggi, A. Rubartelli, and M. R. Zocchi
Involvement of Dihydropyridine-sensitive Calcium Channels in Human Dendritic Cell Function. COMPETITION BY HIV-1 TAT
J. Biol. Chem., March 27, 1998; 273(13): 7205 - 7209.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 All ASBMB Journals   Molecular and Cellular Proteomics 
 Journal of Lipid Research   ASBMB Today 
Copyright © 1997 by the American Society for Biochemistry and Molecular Biology.