TY - JOUR
T1 - A non-covalent interaction between small ubiquitin-like modifier-1 and Zac1 regulates Zac1 cellular functions
AU - Liu, Shu Ting
AU - Chang, Yung Lung
AU - Wang, Wei Ming
AU - Chung, Min Huey
AU - Lin, Wei Shiang
AU - Chou, Wei Yuan
AU - Huang, Shih Ming
N1 - Funding Information:
We thank Dr. B.C. Chung (Academia Sinica, Taiwan, ROC) for the Flag-DsRed.SUMO-1 (GG and GA) expression constructs and Dr. W.P. Huang (National Taiwan University, Taiwan, ROC) for the pGFP-LC3 expression construct. RNAi reagents were obtained from the National RNAi Core Facility located at the Institute of Molecular Biology/Genomic Research Center, Academia Sinica, supported by the National Research Program for Genomic Medicine Grants of NSC (NSC 97-3112-B-001-016). This work was supported by grants from the National Science Council and Ministry of National Defense-Medical Affairs Bureau, Taiwan, Republic of China ( NSC 98-2320-B-016-012-MY3 to SM Huang; NSC 99-2314-B-016-005-MY3 to WM Wang; DOD100-C02-04 to WY Chou).
PY - 2012/3
Y1 - 2012/3
N2 - Zac1, a zinc-finger protein that regulates apoptosis and cell cycle arrest 1, such as p53, can induce cell-cycle arrest and apoptosis. The transactivation and coactivation functions of Zac1 may occur at non-promyelocytic leukemia nuclear body (PML-NB) sites in the presence of other PML-NB components, including ubiquitin-conjugating 9 (Ubc9). It is unclear whether post-translational modification of Zac1 by the small ubiquitin-like modifier SUMO plays a role in the coactivation functions of Zac1 for the regulation of the p21 gene. Mutagenesis experiments revealed that the two SUMO-binding lysine residues of Zac1, K237 and K424, repress the transactivation activity of Zac1. Studies using a SUMO-1 C-terminal di-glycine motif mutant that is deficient in the ability to form covalent bonds with lysines, SUMO-1 (GA), and a dominant-negative Ubc9 construct (C93S) indicated that SUMO-1 might regulate Zac1 transactivation and coactivation via a non-covalent interaction. Unlike the wild-type Zac1, which induced apoptosis, the Zac1 (K237/424R) double mutant had the ability to induce autophagy. The functional role of p21 remains to be investigated. SUMO-1 selectively suppressed the induction of the p21 gene and protein by wild-type Zac1 but not by the Zac1 (K237/424R) double mutant. Moreover, wild-type Ubc9 but not Ubc9 (C93S) further potentiated the suppression of SUMO-1 in all Zac1-induced p21 promoter activities. Our data reveal that p21 may be an important factor for the prevention of Zac1-induced apoptosis without affecting autophagosome formation. This work indicates that Zac1 functions are regulated, at least in part, via non-covalent interactions with SUMO-1 for the induction of p21, which is important for the modulation of apoptosis.
AB - Zac1, a zinc-finger protein that regulates apoptosis and cell cycle arrest 1, such as p53, can induce cell-cycle arrest and apoptosis. The transactivation and coactivation functions of Zac1 may occur at non-promyelocytic leukemia nuclear body (PML-NB) sites in the presence of other PML-NB components, including ubiquitin-conjugating 9 (Ubc9). It is unclear whether post-translational modification of Zac1 by the small ubiquitin-like modifier SUMO plays a role in the coactivation functions of Zac1 for the regulation of the p21 gene. Mutagenesis experiments revealed that the two SUMO-binding lysine residues of Zac1, K237 and K424, repress the transactivation activity of Zac1. Studies using a SUMO-1 C-terminal di-glycine motif mutant that is deficient in the ability to form covalent bonds with lysines, SUMO-1 (GA), and a dominant-negative Ubc9 construct (C93S) indicated that SUMO-1 might regulate Zac1 transactivation and coactivation via a non-covalent interaction. Unlike the wild-type Zac1, which induced apoptosis, the Zac1 (K237/424R) double mutant had the ability to induce autophagy. The functional role of p21 remains to be investigated. SUMO-1 selectively suppressed the induction of the p21 gene and protein by wild-type Zac1 but not by the Zac1 (K237/424R) double mutant. Moreover, wild-type Ubc9 but not Ubc9 (C93S) further potentiated the suppression of SUMO-1 in all Zac1-induced p21 promoter activities. Our data reveal that p21 may be an important factor for the prevention of Zac1-induced apoptosis without affecting autophagosome formation. This work indicates that Zac1 functions are regulated, at least in part, via non-covalent interactions with SUMO-1 for the induction of p21, which is important for the modulation of apoptosis.
KW - Coactivation
KW - SUMO-1
KW - SUMO-interacting motif
KW - SUMOylation
KW - Zac1
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UR - http://www.scopus.com/inward/citedby.url?scp=84862830729&partnerID=8YFLogxK
U2 - 10.1016/j.biocel.2011.12.012
DO - 10.1016/j.biocel.2011.12.012
M3 - Article
C2 - 22227369
AN - SCOPUS:84862830729
SN - 1357-2725
VL - 44
SP - 547
EP - 555
JO - International Journal of Biochemistry and Cell Biology
JF - International Journal of Biochemistry and Cell Biology
IS - 3
ER -