Activity of Protein Kinase CK2 Uncouples Bid Cleavage from Caspase-8 Activation

Authors

Christian T. Hellwig, Royal College of Surgeons in Ireland, Dublin, Ireland
Agnieszka H. Ludwig-Galezowska, Royal College of Surgeons in Ireland, Dublin, Ireland
Caoimhin G. Concannon, Royal College of Surgeons in Ireland, Dublin, Ireland
David W. Litchfield, The University of Western OntarioFollow
Jochen H. M. Prehn, Royal College of Surgeons in Ireland, Dublin, Ireland
Markus Rehm, Royal College of Surgeons in Ireland, Dublin, Ireland

Document Type

Article

Publication Date

5-2010

Journal

Journal of Cell Science

Volume

123

Issue

9

First Page

1401

Last Page

1406

URL with Digital Object Identifier

http://dx.doi.org/10.1242/jcs.061143

Abstract

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.