DAP kinase and DRP-1 mediate membrane blebbing and the formation of autophagic vesicles during programmed cell death.
Death-associated protein kinase (DAPk) and DAPk-related protein kinase (DRP)-1 proteins are Ca+2/calmodulin-regulated Ser/Thr death kinases whose precise roles in programmed cell death are still mostly unknown. In this study, we dissected the subcellular events in which these kinases are involved during cell death. Expression of each of these DAPk subfamily members in their activated forms triggered two major cytoplasmic events: membrane blebbing, characteristic of several types of cell death, and extensive autophagy, which is typical of autophagic (type II) programmed cell death. These two different cellular outcomes were totally independent of caspase activity. It was also found that dominant negative mutants of DAPk or DRP-1 reduced membrane blebbing during the p55/tumor necrosis factor receptor 1-induced type I apoptosis but did not prevent nuclear fragmentation. In addition, expression of the dominant negative mutant of DRP-1 or of DAPk antisense mRNA reduced autophagy induced by antiestrogens, amino acid starvation, or administration of interferon-gamma. Thus, both endogenous DAPk and DRP-1 possess rate-limiting functions in these two distinct cytoplasmic events. Finally, immunogold staining showed that DRP-1 is localized inside the autophagic vesicles, suggesting a direct involvement of this kinase in the process of autophagy.
Inbal
Boaz
B
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
Bialik
Shani
S
Sabanay
Ilana
I
Shani
Gidi
G
Kimchi
Adi
A
D015703:Antigens, CD / Q000378:metabolism; D017209:Apoptosis / Q000235:genetics; D051017:Apoptosis Regulatory Proteins; D001343:Autophagy / Q000502:physiology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000473:pathology*; D064550:Death-Associated Protein Kinases; D006367:HeLa Cells; D006801:Humans; D007371:Interferon-gamma / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D016372:RNA, Antisense / Q000096:biosynthesis; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism; D047888:Receptors, Tumor Necrosis Factor, Type I; D022161:Transport Vesicles / Q000502:physiology; D014407:Tumor Cells, Cultured; D000098855:Collapsin Response Mediator Protein 1
D015703:Antigens, CD; D051017:Apoptosis Regulatory Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020169:Caspases; D064550:Death-Associated Protein Kinases; D007371:Interferon-gamma; D009419:Nerve Tissue Proteins; D016372:RNA, Antisense; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; C102924:CRMP1 protein, human; D000098855:Collapsin Response Mediator Protein 1