Caspase recruitment domain of procaspase-2 could be a target for SUMO-1 modification through Ubc9.
To identify the binding proteins that regulate the function of procaspase-2, we screened for proteins using the yeast two-hybrid method and isolated human Ubc9 and SUMO-1 as the candidates. Ubc9 and SUMO-1 interacted with the caspase recruitment domain of procaspase-2 in its N-terminal. We elucidated the covalent modification of procaspase-2 by SUMO-1 in mammalian cells by immunoprecipitation followed by Western blot analysis. Procaspase-2 and SUMO-1 were co-localized by dot-like structures in the nucleus that are related to promyelocytic leukemia bodies. Interestingly, a conjugation-deficient mutant (K60R) procaspase-2 resulted in a delay of its enzyme maturation (appearance of p12 subunit) compared to that of wild-type. Thus, the modification with SUMO-1 may play a critical role in the nuclear localization and the activation (maturation) of procaspase-2.
Shirakura
Hiromi
H
Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
Hayashi
Naoko
N
Ogino
Shin-ichi
S
Tsuruma
Kazuhiro
K
Uehara
Takashi
T
Nomura
Yasuyuki
Y
D015153:Blotting, Western; D053143:Caspase 2; D020169:Caspases / Q000378:metabolism*; D004789:Enzyme Activation; D025842:SUMO-1 Protein / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism*; D000098843:Ubiquitin-Conjugating Enzyme UBC9
D025842:SUMO-1 Protein; D044763:Ubiquitin-Conjugating Enzymes; D053143:Caspase 2; D020169:Caspases; D000098843:Ubiquitin-Conjugating Enzyme UBC9