Enables 2',3'-cyclic GMP-AMP binding activity; 3',2'-cyclic GMP-AMP binding activity; and cyclic-di-GMP binding activity. Involved in several processes, including positive regulation of defense response; response to bacterium; and response to virus. Located in endoplasmic reticulum membrane. Human ortholog(s) of this gene implicated in STING-associated vasculopathy with onset in infancy. Orthologous to human STING1 (stimulator of interferon response cGAMP interactor 1).