Cargando…

Residual active granzyme B in cathepsin C–null lymphocytes is sufficient for perforin-dependent target cell apoptosis

Cathepsin C activates serine proteases expressed in hematopoietic cells by cleaving an N-terminal dipeptide from the proenzyme upon granule packaging. The lymphocytes of cathepsin C–null mice are therefore proposed to totally lack granzyme B activity and perforin-dependent cytotoxicity. Surprisingly...

Descripción completa

Detalles Bibliográficos
Autores principales: Sutton, Vivien R., Waterhouse, Nigel J., Browne, Kylie A., Sedelies, Karin, Ciccone, Annette, Anthony, Desiree, Koskinen, Aulikki, Mullbacher, Arno, Trapani, Joseph A.
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 2007
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2063978/
https://www.ncbi.nlm.nih.gov/pubmed/17283185
http://dx.doi.org/10.1083/jcb.200609077
Descripción
Sumario:Cathepsin C activates serine proteases expressed in hematopoietic cells by cleaving an N-terminal dipeptide from the proenzyme upon granule packaging. The lymphocytes of cathepsin C–null mice are therefore proposed to totally lack granzyme B activity and perforin-dependent cytotoxicity. Surprisingly, we show, using live cell microscopy and other methodologies, that cells targeted by allogenic CD8(+) cytotoxic T lymphocyte (CTL) raised in cathepsin C–null mice die through perforin-dependent apoptosis indistinguishable from that induced by wild-type CTL. The cathepsin C–null CTL expressed reduced but still appreciable granzyme B activity, but minimal granzyme A activity. Also, in contrast to mice with inactivation of both their granzyme A/B genes, cathepsin C deficiency did not confer susceptibility to ectromelia virus infection in vivo. Overall, our results indicate that although cathepsin C clearly generates the majority of granzyme B activity, some is still generated in its absence, pointing to alternative mechanisms for granzyme B processing and activation. Cathepsin C deficiency also results in considerably milder immune deficiency than perforin or granzyme A/B deficiency.