AKAP12 variant 1 knockout enhances vascular endothelial cell motility

This study investigates the role of AKAP12 in endothelial cell motility with a specific focus on AKAP12 variants, AKAP12v1 and AKAP12v2. Previous work has shown that AKAP12, a multivalent A-kinase anchoring protein that binds to PKA and several other proteins regulating protein phosphorylation, is expressed at low levels in most endothelia in vivo but is expressed at higher levels in cells in vitro. Here, we found that AKAP12 expression in endothelial cell (HUVEC) cultures was cell density-dependent, with the expression being highest in subconfluent cultures and lowest in confluent cultures. AKAP12 expression was also elevated in cells at the wound edge of wounded endothelial cell monolayers. Knockdown of variants 1 and 2 inhibited cell migration. However, CRISPR/Cas9 knockout of AKAP12v1 enhanced migration, indicating that the absence of this variant and the presence of AKAP12v2 likely alters the signaling events controlling cell motility. Further analysis using bulk RNA sequencing revealed that the loss of AKAP12v1 affected genes associated with cell migration and intercellular junctions. We propose that AKAP12v1 and AKAP12v2 play distinct yet complementary roles in endothelial cell migration and likely work together in controlling the signaling events associated with vascular repair and development.