Structural association of Bax with nuclear matrix and cytomatrix revealed by embedment-free immunogold electron microscopy.
Bax is a cellular protein functioning as a promoter of apoptosis. It is ultrastructurally associated with mitochondrial membranes, where it participates in permeability transition pore formation. By employing embedment-free electron microscopy (EFEM), we present evidence that Bax is also associated with the nuclear matrix and cytomatrix of cultured human tumour cells (COLO 205, PA-1, U-373 MG). Extracted cellular scaffolds were probed with anti-Bax antibody using the immunogold electron microscopy technique. Bax immunoreactivity was found on 10-15 nm intermediate filaments of karyo- and cytoskeleton, stretched between the nucleus, nuclear lamina and cell periphery. Bax immunoreactivity was preferentially localized to certain areas of filaments (spot-like). The target molecules for Bax binding in the cellular matrix and their physiological significance remain to be established.
Gajkowska
B
B
Laboratory of the Cell Ultrastructure, Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland. gajk@cmdik.pan.pl
Motyl
T
T
Olszewska-Badarczuk
H
H
Gniadecki
R
R
Koronkiewicz
M
M
D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron / Q000379:methods; D015530:Nuclear Matrix / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein