TUCAN, an antiapoptotic caspase-associated recruitment domain family protein overexpressed in cancer.
Caspase-associated recruitment domains (CARDs) are protein interaction domains that participate in activation or suppression of CARD-carrying members of the caspase family of apoptosis-inducing proteases. A novel CARD-containing protein was identified that is overexpressed in some types of cancer and that binds and suppresses activation of procaspase-9, which we term TUCAN (tumor-up-regulated CARD-containing antagonist of caspase nine). The CARD domain of TUCAN selectively binds itself and procaspase-9. TUCAN interferes with binding of Apaf1 to procaspase-9 and suppresses caspase activation induced by the Apaf1 activator, cytochrome c. Overexpression of TUCAN in cells by stable or transient transfection inhibits apoptosis and caspase activation induced by Apaf1/caspase-9-dependent stimuli, including Bax, VP16, and staurosporine, but not by Apaf1/caspase-9-independent stimuli, Fas and granzyme B. High levels of endogenous TUCAN protein were detected in several tumor cell lines and in colon cancer specimens, correlating with shorter patient survival. Thus, TUCAN represents a new member of the CARD family that selectively suppresses apoptosis induced via the mitochondrial pathway for caspase activation.
Pathan
N
N
Burnham Institute, La Jolla, California 92037, USA.
Marusawa
H
H
Krajewska
M
M
Matsuzawa
S
S
Kim
H
H
Okada
K
K
Torii
S
S
Kitada
S
S
Krajewski
S
S
Welsh
K
K
Pio
F
F
Godzik
A
A
Reed
J C
JC
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D017209:Apoptosis; D053477:Apoptotic Protease-Activating Factor 1; D001483:Base Sequence; D053468:CARD Signaling Adaptor Proteins; D053453:Caspase 9; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D017931:DNA Primers; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000037:antagonists & inhibitors / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D019169:Jurkat Cells; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009369:Neoplasms / Q000201:enzymology; D011485:Protein Binding; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid
C506592:APAF1 protein, human; D048868:Adaptor Proteins, Signal Transducing; D053477:Apoptotic Protease-Activating Factor 1; D053468:CARD Signaling Adaptor Proteins; C455623:CARD8 protein, human; D061945:Caspase Inhibitors; D017931:DNA Primers; D004792:Enzyme Precursors; D009363:Neoplasm Proteins; D011506:Proteins; C506433:CASP9 protein, human; D053453:Caspase 9; D020169:Caspases