AKT isoforms have distinct hippocampal expression and roles in synaptic plasticity

Area of Science:

• Neuroscience
• Molecular Biology
• Cellular Biology

Background:

• The serine/threonine kinase AKT regulates critical cellular processes, with mutations impacting brain function.
• AKT's role in synaptic plasticity is indirect, and the specific functions of its three brain-expressed isoforms (AKT1, AKT2, AKT3) remain unclear.

Purpose of the Study:

• To investigate the distinct expression patterns and functional roles of AKT isoforms in the hippocampus.
• To elucidate the involvement of AKT isoforms in different forms of hippocampal synaptic plasticity.

Main Methods:

• Utilized immunohistochemistry to determine the expression patterns of AKT1, AKT2, and AKT3 in the mouse hippocampus.
• Employed electrophysiological techniques to assess the roles of AKT isoforms in long-term potentiation (LTP) and long-term depression (LTD) in the CA1 region.

Main Results:

• Each AKT isoform exhibits a unique hippocampal expression profile: AKT1 and AKT3 are neuronal, while AKT2 is astrocytic.
• AKT1 is essential for activity-induced protein synthesis underlying long-term potentiation (LTP).
• AKT activity, involving both AKT1 and AKT3, inhibits metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD).

Conclusions:

• The three AKT isoforms display differential localization within the hippocampus.
• AKT isoforms play isoform-specific roles in regulating hippocampal synaptic plasticity, highlighting their distinct contributions to neuronal function.