Localization of cAMP-dependent protein kinase in the actin and microtubule cytoskeletons in mouse hippocampal neurons.

Cyclic adenosine monophosphate-dependent protein kinase (PKA) is involved in various biological functions in neurons. To investigate the subcellular localization of PKA, we stained cultured hippocampal neurons with anti-PKA catalytic subunit antisera. PKA catalytic subunit colocalized with microtubules (MTs) in dendrites as well as with the actin filaments (F-actin) in growth cones. After treatment with cytochalasin B, the colocalization of PKA catalytic subunits with MTs was enhanced, whereas the colocalization with F-actin was suppressed. This result indicates that PKA is anchored to the actin and MT cytoskeletons, and disruption of F-actin releases PKA to the cytoplasm, which then leads to an increase in the amount of PKA in MT domains in the neuron.