La autoantigen translocates to cytoplasm after cleavage during granzyme B-mediated cytotoxicity.
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.
Huang
Mingguo
M
Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan. idah@net.nagasaki-u.ac.jp
Ida
Hiroaki
H
Arima
Kazuhiko
K
Nakamura
Hideki
H
Aramaki
Toshiyuki
T
Fujikawa
Keita
K
Tamai
Mami
M
Kamachi
Makoto
M
Kawakami
Atsushi
A
Yamasaki
Hironori
H
Origuchi
Tomoki
T
Eguchi
Katsumi
K
D001324:Autoantigens / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism*; D053804:Granzymes / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D018613:Microscopy, Confocal; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D000097585:SS-B Antigen
D001324:Autoantigens; D053804:Granzymes; D049452:Green Fluorescent Proteins; D011993:Recombinant Fusion Proteins; D012261:Ribonucleoproteins; D000097585:SS-B Antigen