creators_name: Kathania, Mahesh
creators_name: Raje, Chaaya Iyengar
creators_name: Raje, Manoj
creators_name: Dutta, Rajesh Kumar
creators_name: Majumdar, Sekhar
type: article
datestamp: 2011-12-08 18:56:31
lastmod: 2011-12-08 18:56:31
metadata_visibility: show
title: Bfl-1/A1 acts as a negative regulator of autophagy in mycobacteria infected macrophages.
ispublished: pub
subjects: QD
full_text_status: none
keywords: TACO, tryptophan–aspartate containing coat protein; mTOR, mammalian target of rapamycin; PI3K, phosphatidylinositol 3-kinase; LC3, microtubule-associated protein 1 light chain 3
note: Copyright of this article belongs to Elsevier Science
abstract: Expression of Bcl-2 family protein, Bfl-1/A1 has been found to differ considerably amongst macrophages infected with virulent Mycobacterium tuberculosis H37Rv or with avirulent M. tuberculosis H37Ra. Present work was undertaken to deduce the significance of differential expression of Bfl-1/A1 in the outcome of mycobacterial infection. We have studied the role of Bfl-1/A1 particularly in autophagy formation in tubercle bacilli infected cells since autophagy has been recognized as a component of innate immunity against pathogenic mycobacteria. First, we have confirmed that upon infection virulent strain H37Rv retain Bfl-1/A1 for longer period and impose autophagosome maturation block within infected cells as evident from confocal microscopy. Moreover, down regulation of Bfl-1/A1 by siRNA induced autophagy formation and reduced bacterial growth. Furthermore, even the avirulent strain H37Ra resist autophagosome maturation and survive if the cellular level of Bfl-1 is maintained in THP-1 cells by stable transfection (Bfl-1 overexpressing cells). No noteworthy difference in mTOR expression was observed between normal THP-1 and Bfl-1 overexpressing THP-1 cells infected with either strain of mycobacteria. Interestingly, we found that not only mTOR but also Bfl-1/A1 is involved in rapamycin induced autophagy in mycobacteria infected macrophages. We have found that Bfl-1 physically interacts with Beclin 1 in Bfl-1 overexpressing THP-1 as well as in H37Rv infected THP-1 cells as they co-precipitated. Taken together, our results clearly demonstrated that Bfl-1/A1 negatively regulates autophagy and expression of Bfl-1/A1 in H37Rv infected macrophages provides the bacteria a survival strategy to overcome host defense.
date: 2011-04
date_type: published
publication: The international journal of biochemistry & cell biology
volume: 43
number: 4
publisher: Elsevier Science
pagerange: 573-85
refereed: TRUE
issn: 1878-5875
official_url: http://www.sciencedirect.com/science/article/pii/S1357272510004267
related_url_url: http://www.sciencedirect.com/science/article/pii/S1357272510004267
related_url_type: pub
citation:   Kathania, Mahesh and Raje, Chaaya Iyengar and Raje, Manoj and Dutta, Rajesh Kumar and Majumdar, Sekhar  (2011) Bfl-1/A1 acts as a negative regulator of autophagy in mycobacteria infected macrophages.  The international journal of biochemistry & cell biology, 43 (4).  pp. 573-85.  ISSN 1878-5875