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Am J Translational Res 2011;3(2):121-132
Original Article
Regulation of the oncoprotein KLF8 by a switch between acetylation
and sumoylation
Alison M. Urvalek, Heng Lu, Xianhui Wang, Tianshu Li, Lin Yu, Jinghua Zhu, Qishan Lin, Jihe Zhao
Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Center for Functional
Genomics, University at Albany, Rensselaer, NY 12144, Current address: Department of Pharmacology, Weill
Medical College of Cornell University, New York, NY 10065, Current address: Ge*NY*sis Center for Excellence in
Cancer Genomics, University at Albany, Rensselaer, NY 12144.
Received November 11, 2010; Accepted November 20, 2010; Epub November 21, 2010; Published January 1,
2011
Abstract: KLF8 regulates target genes by recruiting the p300 and PCAF co-activators via glutamines (Q) 118 and
248, the CtBP co-repressor to 86PVDLS90 or SUMO to lysine (K) 67. Here we examined how these interactions
coordinate to regulate KLF8 transactivity. Mass spectrometry and immunoprecipitations determined that p300
and/or PCAF promoted KLF8 acetylation at K67, K93, and K95 and this acetylation was abolished in
lysine-to-arginine (R) mutants. Treatment with HDAC inhibitors or expression of co-activators inhibited
sumoylation at K67. K93R or K95R mutation exerted high levels of sumoylation while the acetylation mimetic
mutations K93Q and K95Q blocked the sumoylation. Interestingly, CtBP promoted sumoylation at K67 of wild-type
but not AVALF mutant KLF8, and KLF8 interaction with CtBP was inhibited by treatment with the HDAC inhibitors,
ectopic expression of the co-activators, or K93Q or K95Q mutation. Promoter reporter assays showed that CtBP
inhibited KLF8 transactivity which was rescued by PCAF or p300 expresson. Finally, KLF8-mediated cyclin D1
protein expression and cell cycle progression was significantly decreased in the K93R and K95R but increased
in the K93Q, K95Q, K67R or K67Q mutant. Taken together, these results identified a novel mechanism by which
co-activators promote KLF8 transactivity by competing with SUMO for K67 modification and by acetylating K93 and
K95 to inhibit CtBP-induced K67 sumoylation. (AJTR1011002).
Keywords: Krüppel-like factor 8 (KLF8), histone acetyltransferase (HAT), small ubiquitin modifier (SUMO), p300,
p300/CBP associated factor (PCAF), histone deacetylase (HDAC), C-terminal binding protein (CtBP), acetylation
and sumoylation
Full Text PDF
Address all correspondence to:
Jihe Zhao, MD, PhD
Burnett School of Biomedical Sciences
College of Medicine, University of Central Florida
Orlando, FL 32827,
Tel: 407-266-7099, Fax: 407-266-7002
E-mail: jizhao@mail.ucf.edu
Original Article
Regulation of the oncoprotein KLF8 by a switch between acetylation
and sumoylation
Alison M. Urvalek, Heng Lu, Xianhui Wang, Tianshu Li, Lin Yu, Jinghua Zhu, Qishan Lin, Jihe Zhao
Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Center for Functional
Genomics, University at Albany, Rensselaer, NY 12144, Current address: Department of Pharmacology, Weill
Medical College of Cornell University, New York, NY 10065, Current address: Ge*NY*sis Center for Excellence in
Cancer Genomics, University at Albany, Rensselaer, NY 12144.
Received November 11, 2010; Accepted November 20, 2010; Epub November 21, 2010; Published January 1,
2011
Abstract: KLF8 regulates target genes by recruiting the p300 and PCAF co-activators via glutamines (Q) 118 and
248, the CtBP co-repressor to 86PVDLS90 or SUMO to lysine (K) 67. Here we examined how these interactions
coordinate to regulate KLF8 transactivity. Mass spectrometry and immunoprecipitations determined that p300
and/or PCAF promoted KLF8 acetylation at K67, K93, and K95 and this acetylation was abolished in
lysine-to-arginine (R) mutants. Treatment with HDAC inhibitors or expression of co-activators inhibited
sumoylation at K67. K93R or K95R mutation exerted high levels of sumoylation while the acetylation mimetic
mutations K93Q and K95Q blocked the sumoylation. Interestingly, CtBP promoted sumoylation at K67 of wild-type
but not AVALF mutant KLF8, and KLF8 interaction with CtBP was inhibited by treatment with the HDAC inhibitors,
ectopic expression of the co-activators, or K93Q or K95Q mutation. Promoter reporter assays showed that CtBP
inhibited KLF8 transactivity which was rescued by PCAF or p300 expresson. Finally, KLF8-mediated cyclin D1
protein expression and cell cycle progression was significantly decreased in the K93R and K95R but increased
in the K93Q, K95Q, K67R or K67Q mutant. Taken together, these results identified a novel mechanism by which
co-activators promote KLF8 transactivity by competing with SUMO for K67 modification and by acetylating K93 and
K95 to inhibit CtBP-induced K67 sumoylation. (AJTR1011002).
Keywords: Krüppel-like factor 8 (KLF8), histone acetyltransferase (HAT), small ubiquitin modifier (SUMO), p300,
p300/CBP associated factor (PCAF), histone deacetylase (HDAC), C-terminal binding protein (CtBP), acetylation
and sumoylation
Full Text PDF
Address all correspondence to:
Jihe Zhao, MD, PhD
Burnett School of Biomedical Sciences
College of Medicine, University of Central Florida
Orlando, FL 32827,
Tel: 407-266-7099, Fax: 407-266-7002
E-mail: jizhao@mail.ucf.edu
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