Activity of protein kinase CK2 uncouples Bid cleavage from caspase-8 activation.
In the present study, we quantitatively analysed the interface between apoptosis initiation and execution by determining caspase-8 activation, Bid cleavage and mitochondrial engagement (onset of mitochondrial depolarisation) in individual HeLa cervical cancer cells following exposure to tumour-necrosis-factor-related apoptosis-inducing ligand (TRAIL). Employing resonance-energy-transfer probes containing either the caspase-8 recognition site IETD or full-length Bid, we observed a significant delay between the times of caspase-8 activation and Bid cleavage, suggesting the existence of control steps separating these two processes. Subsequent analyses suggested that the divergence of caspase-8 activation and Bid cleavage are critically controlled by kinase signalling: inhibiting protein kinase CK2 by using 5,6-dichloro-l-(beta-D-ribofuranosyl-1)-benzimidazole (DRB) or by overexpression of a dominant-negative CK2alpha catalytic subunit largely eliminated the lag time between caspase-8 activation and Bid cleavage. We conclude that caspase-8 activation and Bid cleavage are temporally uncoupled events, providing transient tolerance to caspase-8 activities.
Hellwig
Christian T
CT
Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, RCSI York House, York Street, Dublin 2, Ireland.
Ludwig-Galezowska
Agnieszka H
AH
Concannon
Caoimhin G
CG
Litchfield
David W
DW
Prehn
Jochen H M
JH
Rehm
Markus
M
D017209:Apoptosis / Q000187:drug effects; D051023:BH3 Interacting Domain Death Agonist Protein / Q000378:metabolism*; D047390:Casein Kinase II / Q000037:antagonists & inhibitors / Q000378:metabolism*; D053181:Caspase 8 / Q000737:chemistry / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D031541:Fluorescence Resonance Energy Transfer; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D015398:Signal Transduction / Q000187:drug effects; D013379:Substrate Specificity / Q000187:drug effects; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology; D013997:Time Factors
D051023:BH3 Interacting Domain Death Agonist Protein; D047428:Protein Kinase Inhibitors; D053221:TNF-Related Apoptosis-Inducing Ligand; D047390:Casein Kinase II; D053181:Caspase 8