Long-term dynamic profiles of cognitive kinases induced by different learning protocols.

Area of Science:

• Neuroscience
• Molecular Biology
• Cellular Signaling

Background:

• Learning involves protein kinase activation, but dynamics vary with learning protocols.
• Long-term synaptic facilitation (LTF) in Aplysia is crucial for memory.
• Previous work examined ERK dynamics; this study investigates p38 MAPK, PKA, and RSK.

Purpose of the Study:

• To examine the long-term activation dynamics of key kinases (p38 MAPK, PKA, RSK) following different learning protocols in Aplysia.
• To compare kinase dynamics across Standard, Enhanced, and two-pulse protocols.
• To understand the molecular mechanisms underlying LTF and long-term memory.

Main Methods:

• Investigated long-term (24h) dynamics of p38 MAPK, PKA, and RSK activity.
• Utilized three distinct serotonin (5-HT) learning protocols: Standard, Enhanced, and a two-pulse protocol.
• Analyzed kinase activity patterns, including waves of activation and return to basal levels.

Main Results:

• All four kinases (ERK, p38 MAPK, PKA, RSK) exhibited complex biphasic activity within 24 hours.
• A first wave of kinase activity occurred within 5 hours, followed by a second wave from 5 to 18 hours.
• The Enhanced protocol uniquely maintained elevated kinase activity at 24 hours, unlike Standard and two-pulse protocols.

Conclusions:

• Complex kinase dynamics, involving feedback loops and growth factors (NT, TGF-β), underlie LTF.
• The Enhanced protocol's sustained kinase activation may be key for robust long-term memory.
• Findings inform potential strategies for optimizing training protocols for memory enhancement.