Publications

• Novel Mechanism for Cyclic Dinucleotide Degradation Revealed by Structural Studies of Vibrio Phosphodiesterase V-cGAP3.

  Deng M.J., Tao J., Chao E., Ye Z.Y., Jiang Z., Yu J., Su X.D.

  3'3'-cyclic GMP-AMP (3'3'-cGAMP) belongs to a family of the bacterial secondary messenger cyclic dinucleotides. It was first discovered in the Vibrio cholerae seventh pandemic strains and is involved in efficient intestinal colonization and chemotaxis regulation. Phosphodiesterases (PDEs) that deg ... >> More

  3'3'-cyclic GMP-AMP (3'3'-cGAMP) belongs to a family of the bacterial secondary messenger cyclic dinucleotides. It was first discovered in the Vibrio cholerae seventh pandemic strains and is involved in efficient intestinal colonization and chemotaxis regulation. Phosphodiesterases (PDEs) that degrade 3'3'-cGAMP play important regulatory roles in the relevant signaling pathways, and a previous study has identified three PDEs in V. cholerae, namely, V-cGAP1, V-cGAP2, and V-cGAP3, functioning in 3'3'-cGAMP degradation. We report the crystal structure, biochemical, and structural analyses of V-cGAP3, providing a foundation for understanding the mechanism of 3'3'-cGAMP degradation and regulation in general. Our crystal and molecular dynamic (MD)-simulated structures revealed that V-cGAP3 contains tandem HD-GYP domains within its N- and C-terminal domains, with similar three-dimensional topologies despite their low-sequence identity. Biochemical and structural analyses showed that the N-terminal domain plays a mechanism of positive regulation for the catalytic C-terminal domain. We also demonstrated that the other homologous Vibrio PDEs, V-cGAP1/2, likely function via a similar mechanism. << Less

  J. Mol. Biol. 430:5080-5093(2018) [PubMed] [EuropePMC]

• Identification and characterization of phosphodiesterases that specifically degrade 3'3'-cyclic GMP-AMP.

  Gao J., Tao J., Liang W., Zhao M., Du X., Cui S., Duan H., Kan B., Su X., Jiang Z.

  Cyclic dinucleotides act as intracellular second messengers, modulating a variety of cellular activities including innate immune activation. Although phosphodiesterases (PDEs) hydrolyzing c-di-GMP and c-di-AMP have been identified, no PDEs for cGAMPs have been reported. Here we identified the firs ... >> More

  Cyclic dinucleotides act as intracellular second messengers, modulating a variety of cellular activities including innate immune activation. Although phosphodiesterases (PDEs) hydrolyzing c-di-GMP and c-di-AMP have been identified, no PDEs for cGAMPs have been reported. Here we identified the first three cGAMP-specific PDEs in V. cholerae (herein designated as V-cGAP1/2/3). V-cGAPs are HD-GYP domain-containing proteins and specifically break 3'3'-cGAMP, but not other forms of cGAMP. 3'3'-cGAMP is first linearized by all three V-cGAPs to produce 5'-pApG, which is further hydrolyzed into 5'-ApG by V-cGAP1. In this two-step reaction, V-cGAP1 functions as both a PDE and a 5'-nucleotidase. In vivo experiments demonstrated that V-cGAPs play non-redundant roles in cGAMP degradation. The high specificity of V-cGAPs on 3'3'-cGAMP suggests the existence of specific PDEs for other cGAMPs, including 2'3'-cGAMP in mammalian cells. The absolute requirement of the GYP motif for 3'3'-cGAMP degradation suggests that HD domain-containing PDEs in eukaryotes are probably unable to hydrolyze cGAMPs. The fact that all V-cGAPs attack 3'3'-cGAMP on one specific phosphodiester bond suggests that PDEs for other cGAMPs would utilize a similar strategy. These results will provide valuable information for identification and characterization of mammalian 2'3'-cGAMP-specific PDEs in future studies. << Less

  Cell Res. 25:539-550(2015) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.