Synthesize the process of G protein activation and inactivation in a signaling pathway.

G proteins are activated by ATP binding, leading to downstream signaling, and inactivated by ADP binding.

G proteins are activated by GTP binding, leading to downstream signaling, and inactivated by GDP binding.

G proteins are activated by ADP binding, leading to downstream signaling, and inactivated by ATP binding.

G proteins are activated by GDP binding, leading to downstream signaling, and inactivated by GTP binding.