Protein disulfide isomerase is cleaved by caspase-3 and -7 during apoptosis.
Apoptotic signals are typically accompanied by activation of aspartate-specific cysteine proteases called caspases, and caspase-3 and -7 play crucial roles in the execution of apoptosis. Previously, using the proteomic approach, protein disulfide isomerase (PDI) was found to be a candidate substrate of caspase-7. This abundant 55 kDa protein introduces disulfide bonds into proteins (via its oxidase activity) and catalyzes the rearrangement of incorrect disulfide bonds (via its isomerase activity). PDI is abundant in the ER but is also found in non-ER locations. In this study we demonstrated that PDI is cleaved by caspase-3 and -7 in vitro. In addition, in vivo experiment showed that it is cleaved during etoposide-induced apoptosis in HL-60 cells. Subcellular fractionation showed that PDI was also present in the cytosol. Furthermore, only cytosolic PDI was clearly digested by caspase-3 and -7. It was also confirmed by confocal image analysis that PDI and caspase-7 partially co-localize in both resting and apoptotic MCF-7 cells. Overexpression of cytosolic PDI (ER retention sequence deleted) inhibited cell death after an apoptotic stimulus. These data indicate that cytosolic PDI is a substrate of caspase-3 and -7, and that it has an anti-apoptotic action.
Na
Kyung Sook
KS
Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Korea.
Park
Byoung Chul
BC
Jang
Mi
M
Cho
Sayeon
S
Lee
Do Hee
DH
Kang
Sunghyun
S
Lee
Chong-Kil
CK
Bae
Kwang-Hee
KH
Park
Sung Goo
SG
D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism*; D053179:Caspase 7 / Q000378:metabolism*; D003600:Cytosol / Q000187:drug effects / Q000201:enzymology; D005047:Etoposide / Q000494:pharmacology; D018922:HL-60 Cells; D006801:Humans; D018613:Microscopy, Confocal; D019704:Protein Disulfide-Isomerases / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D011994:Recombinant Proteins / Q000378:metabolism; D013347:Subcellular Fractions / Q000201:enzymology; D013379:Substrate Specificity
D011994:Recombinant Proteins; D005047:Etoposide; D053148:Caspase 3; D053179:Caspase 7; D019704:Protein Disulfide-Isomerases