Apoptotic and necrotic blebs in epithelial cells display similar neck diameters but different kinase dependency.
Apoptotic and necrotic blebs elicited by H(2)O(2) were compared in terms of dynamics, structure and underlying biochemistry in HeLa cells and Clone 9 cells. Apoptotic blebs appeared in a few minutes and required micromolar peroxide concentrations. Necrotic blebs appeared much later, prior to cell permeabilization, and required millimolar peroxide concentrations. Strikingly, necrotic blebs grew at a constant rate, which was unaffected throughout successive cycles of budding and detachment. At 1 microm diameter, the necks of necrotic and apoptotic blebs were almost identical. ATP depletion was discarded as a major factor for both types of bleb. Inhibition of ROCK-I, MLCK and p38MAPK strongly decreased apoptotic blebbing but had no effect on necrotic blebbing. Taken together, these data suggest the existence of a novel structure of fixed dimensions at the neck of both types of plasma membrane blebs in epithelial cells. However, necrotic blebs can be distinguished from apoptotic blebs in their susceptibility to actomyosin kinase inhibition.
Barros
L F
LF
Department of Cell Physiology, National Institute for Physiological Sciences, School of Life Science, Okazaki, Aichi 444-8585, Japan. fbarros@cecs.cl
Kanaseki
T
T
Sabirov
R
R
Morishima
S
S
Castro
J
J
Bittner
C X
CX
Maeno
E
E
Ando-Akatsuka
Y
Y
Okada
Y
Y
D000205:Actomyosin / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D017209:Apoptosis / Q000502:physiology*; D022081:Cell Surface Extensions / Q000187:drug effects / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009336:Necrosis; D010455:Peptides / Q000037:antagonists & inhibitors / Q000378:metabolism; D010770:Phosphotransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases; D054460:rho-Associated Kinases
D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D010455:Peptides; C065738:MLCK peptide; D000255:Adenosine Triphosphate; D000205:Actomyosin; D006861:Hydrogen Peroxide; D010770:Phosphotransferases; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases