Differential localization of ICAD-L and ICAD-S in cells due to removal of a C-terminal NLS from ICAD-L by alternative splicing.
CAD/CPAN/DFF40 is an apoptotic nuclease that is associated with the regulatory subunit ICAD/DFF in healthy cells. ICAD has two forms, ICAD-L/DFF45 and ICAD-S/DFF35, which are transcribed from a single gene by alternative splicing. They differ at the C-terminus: 70 amino acids of ICAD-L are replaced by 4 different amino acids in ICAD-S. We previously showed that both transfected and endogenous ICAD-L are nuclear; however, the localization of ICAD and CAD remains controversial and an important issue to clarify. Here we present the evidence that ICAD-L is nuclear due to the presence of an autonomous nuclear localization signal located in the C-terminal 20 amino acids. This NLS is missing from ICAD-S, which is distributed throughout the cell. We also showed that a GFP:CAD fusion protein is located in the nucleus of transfected cells.
Samejima
K
K
Institute of Cell and Molecular Biology, University of Edinburgh, Edinburgh, Scotland, EH9 3JR, United Kingdom.
Earnshaw
W C
WC
D017398:Alternative Splicing; D051017:Apoptosis Regulatory Proteins; D001692:Biological Transport / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011506:Proteins / Q000235:genetics* / Q000378:metabolism*
D051017:Apoptosis Regulatory Proteins; D020033:Protein Isoforms; D011506:Proteins; C109664:caspase-activated DNase inhibitor