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Updated: Jul 10, 2026

A Colorimetric Assay that Specifically Measures Granzyme B Proteolytic Activity: Hydrolysis of Boc-Ala-Ala-Asp-S-Bzl
Published on: November 28, 2014
La autoantigen translocates to cytoplasm after cleavage during granzyme B-mediated cytotoxicity
Mingguo Huang1, Hiroaki Ida, Kazuhiko Arima
1Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan. idah@net.nagasaki-u.ac.jp
Abstract:
Our recent report demonstrated that apoptosis-specific autoantibodies against granzyme B-induced cleavage fragments of SS-B (La) were found in the sera from patients with primary Sjögren's syndrome. The objective of this study was identified by the intracellular redistribution of La autoantigen during granzyme B-induced apoptosis. We developed green fluorescence protein (GFP)-La and GFP-LaDelta220 (generation of granzyme B-specific cleavage of La protein) fusion proteins. GFP-La protein was localized in the nucleus, whereas the GFP-LaDelta220 protein predominantly existed in the cytoplasm in transformed A293T cells. Nuclear GFP-La protein was translocated to cytoplasm after granzyme B enriched YT cells incubation. La protein in human salivary grand HSG cells is cleaved and translocated from the nucleus to the cytoplasm after YT cell co-cultivation. These results suggest that La protein is cleaved by granzyme B and N-terminal La fragment (27 kD) translocated to the cytoplasm, thus leading to a novel autoantibody production during granzyme B-mediated cytotoxicity.
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