Identification of AKAP150 in presynaptic axon terminals of the Basolateral Amygdala

Abstract

A-kinase Anchoring Proteins (AKAP) are responsible for coordinating cellular processes by binding cAMP-dependent protein kinase A (PKA) and various signaling enzymes to cellular organelles and membranes. Our work involved studying one member of the AKAP family, AKAP150, in the rat brain. The absence of AKAP150 disturbs neuronal processes; AKAP150 knockout mice displayed impaired learning and memory, reduced anxiety, impaired motor skills, lower strength, and increased seizure resistance. In the amgydala, AKAP150 is especially important for auditory fear conditioning and memory consolidation. AKAP150 is also needed for longterm potentiation of synaptic communication to occur. Every tissue contains AKAP150, but its specific sub-cellular localization has remained unknown. To determine the localization of AKAP150, immunohistochemistry was used to detect and label AKAP150 in rat brain tissue. This tissue was mounted onto a block that was cut into ultrathin sections, which were then placed onto grids and imaged with an electron microscope. Previous research has focused on AKAP150 in post-synaptic processes such as dendritic shafts and spines. However, our analysis of EM images indicates that AKAP150 is also found in presynaptic axon terminals. This study suggests that future research into the function of AKAP150 should also consider its role in presynaptic processes such as neurotransmitter release.