RRC ID 39620
Author Ayukawa K, Taniguchi S, Masumoto J, Hashimoto S, Sarvotham H, Hara A, Aoyama T, Sagara J.
Title La autoantigen is cleaved in the COOH terminus and loses the nuclear localization signal during apoptosis.
Journal J. Biol. Chem.
Abstract La autoantigen is a 47-kDa nuclear protein that binds to nascent polymerase III transcripts and a number of viral RNAs. We show that La protein was cleaved to generate a 43-kDa fragment during apoptosis of human leukemic HL-60 cells treated with camptothecin or etoposide. Immunofluorescence microscopy showed that the La protein level was increased in the cytoplasm during apoptosis of HL-60 cells. In addition, UV irradiation of HeLa cells led to the cleavage and redistribution of La protein upon apoptosis. Several lines of evidence show that La protein is cleaved by caspase-3 or closely related proteases at Asp-374 in the COOH terminus. When the full-length (La) and COOH-terminally truncated (La delta C374) forms of La protein were expressed as fusion proteins with green fluorescence protein (GFP), GFP-La delta C374 was predominantly cytoplasmic, whereas GFP-La was localized in the nucleus. These results suggest that La protein loses the nuclear localization signal residing in the COOH terminus upon cleavage and is thus redistributed to the cytoplasm during apoptosis.
Volume 275(44)
Pages 34465-70
Published 2000-11-3
DOI 10.1074/jbc.M003673200
PII M003673200
PMID 10913436
MeSH Animals Antibodies, Monoclonal / biosynthesis Apoptosis* Autoantibodies / biosynthesis Autoantigens / chemistry Autoantigens / immunology Autoantigens / metabolism* Base Sequence Cell Line DNA Primers Humans Hydrolysis Mice Nuclear Localization Signals* Ribonucleoproteins / chemistry Ribonucleoproteins / immunology Ribonucleoproteins / metabolism*
IF 4.106
Times Cited 62
Human and Animal Cells