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Mechanistic and structural studies of the cGAS-STING signalling pathway
Vavřina, Zdeněk ; Maloy Řezáčová, Pavlína (advisor) ; Hudeček, Jiří (referee) ; Kolenko, Petr (referee)
The cyclic GMP-AMP synthase (cGAS) - stimulator of interferon genes (STING) signalling pathway plays a crucial role in the innate immune system. It is activated by pathogen double-stranded DNA (dsDNA) or cyclic dinucleotides, which are secondary messengers of bacteria. This activation leads to the expression of type I interferons and proinflammatory cytokines. The present dissertation examines the interaction between cGAS and its substrates and the relation between the STING protein and its agonists from a mechanistic and structural point of view. The enzyme cGAS is a metazoan intracellular sensor of dsDNA. Upon its binding to DNA, it synthesizes the cyclic dinucleotide 2′,3′-cGAMP, which activates the adaptor protein STING. Besides 2′,3′-cGAMP, STING can also be activated by 3′,3′-cyclic dinucleotides that serve as secondary messengers in bacteria. We investigated various dinucleotide cyclases to better understand their substrate specificity and utilized them for the preparation of novel cyclic dinucleotides activating STING. As the most appropriate for the preparation of 2′,3′-cyclic dinucleotides, we identified mouse cGAS. Additionally, we utilized the enzymes DncV from Vibrio cholerae and DisA from Bacillus thuringiensis for the synthesis of 3′,3′-cyclic dinucleotides. These enzymes exhibit...
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