Within the same cell, different signaling routes can signal through the same kinase. To still function in a specific manner, the kinase is localized in close proximity to its substrates and upstream signaling components. This is best described for cAMP-dependent protein kinase (PKA), which utilizes the diverse family of A-kinase anchoring proteins (AKAPs, >50 identified) for spatiotemporal control.
PKA’s closest homologue is the cGMP-dependent protein kinase (PKG), however many details of its localized signaling are not well understood. Thus far, very little G-kinase anchoring proteins (GKAPs) have been identified, likely because they are lower in abundance than AKAPs. In addition, unlike as for AKAPs, common motifs in GKAPs that mediate the interaction have not been convincingly defined.