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The interactions between SATB1 and F-actin are important for mechanisms of active cell death
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Abstract
Introduction. The direct involvement of nuclear actin filaments in gene transcription and remodeling of chromatin is still debatable. However, nuclear localization of F-actin and its interactions with other nuclear matrix proteins have been reported. The aim of the study was to estimate the interactions between nuclear F-actin and one of the matrix proteins, special AT-rich sequence-binding protein 1 (SATB1), during active cell death induced in vitro by geldanamycin (GA).
Material and methods. The expression of SATB1 was modified by the transfection of non-aggressive breast cancer MCF-7 cells with siRNA against SATB1 or expression plasmid with cloned cDNA of SATB1. The amount and localization of F-actin were altered by changes of cofilin-1 (CFL1) expression in MCF-7 cells. The association between SATB1 and F-actin during GA-induced cell death was analyzed using confocal and transmission electron microscopy.
Results. Our studies revealed the colocalization between nuclear F-actin and SATB1 protein, during GA-induced death of breast cancer MCF-7 cells. The colocalization was enhanced in cells with overexpressed SATB1 and cofilin-1. At the ultrastructural level the SATB1 and F-actin complexes were seen at the border of condensed and decondensed chromatin. The presence of SATB1/F-actin molecular complexes was confirmed by magnetic separation of F-actin and interacting proteins.
Conclusion. We suggest that the molecular interactions between SATB1 and F-actin are necessary for active cell death to occur.
Abstract
Introduction. The direct involvement of nuclear actin filaments in gene transcription and remodeling of chromatin is still debatable. However, nuclear localization of F-actin and its interactions with other nuclear matrix proteins have been reported. The aim of the study was to estimate the interactions between nuclear F-actin and one of the matrix proteins, special AT-rich sequence-binding protein 1 (SATB1), during active cell death induced in vitro by geldanamycin (GA).
Material and methods. The expression of SATB1 was modified by the transfection of non-aggressive breast cancer MCF-7 cells with siRNA against SATB1 or expression plasmid with cloned cDNA of SATB1. The amount and localization of F-actin were altered by changes of cofilin-1 (CFL1) expression in MCF-7 cells. The association between SATB1 and F-actin during GA-induced cell death was analyzed using confocal and transmission electron microscopy.
Results. Our studies revealed the colocalization between nuclear F-actin and SATB1 protein, during GA-induced death of breast cancer MCF-7 cells. The colocalization was enhanced in cells with overexpressed SATB1 and cofilin-1. At the ultrastructural level the SATB1 and F-actin complexes were seen at the border of condensed and decondensed chromatin. The presence of SATB1/F-actin molecular complexes was confirmed by magnetic separation of F-actin and interacting proteins.
Conclusion. We suggest that the molecular interactions between SATB1 and F-actin are necessary for active cell death to occur.
Keywords
SATB1; F-actin; cofilin-1; geldanamycin; apoptosis; MCF-7 cells; protein interactions; confocal microscopy; electron microscopy
About this articleTitle
The interactions between SATB1 and F-actin are important for mechanisms of active cell death
Journal
Folia Histochemica et Cytobiologica
Issue
Article type
Original paper
Pages
152-161
Published online
2015-07-21
Page views
2002
Article views/downloads
1926
DOI
10.5603/fhc.a2015.0018
Pubmed
Bibliographic record
Folia Histochem Cytobiol 2015;53(2):152-161.
Keywords
SATB1
F-actin
cofilin-1
geldanamycin
apoptosis
MCF-7 cells
protein interactions
confocal microscopy
electron microscopy
Authors
Dariusz Grzanka
Anna E. Kowalczyk
Magdalena Izdebska
Anna Klimaszewska-Wisniewska
Maciej Gagat
