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

Area of Science:

• Neuroscience
• Molecular Biology
• Cellular Signaling

Background:

• Learning induces protein kinase activation, but dynamics vary with training protocols.
• Long-term synaptic facilitation (LTF) in Aplysia is crucial for memory.
• Understanding kinase activation patterns is key to memory mechanisms.

Purpose of the Study:

• To investigate the long-term activity dynamics of key kinases (p38 MAPK, PKA, RSK) involved in Aplysia LTF.
• To compare these dynamics across different serotonin (5-HT) learning protocols.
• To elucidate the molecular clock mechanisms underlying memory persistence.

Main Methods:

• Examined long-term (24h) kinase activity following three distinct 5-HT learning protocols in Aplysia sensorimotor synapses.
• Measured activity of p38 MAPK, protein kinase A (PKA), and p90 ribosomal S6 kinase (RSK).
• Analyzed interactions among kinase pathways and growth factors (NT, TGF-β).

Main Results:

• All four kinases (including previously studied ERK) exhibited complex, two-wave activity patterns within 24 hours post-treatment.
• A first wave of kinase activation 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:

• Kinase activation dynamics are complex and protocol-dependent during LTF induction.
• Interactions within kinase pathways and with growth factors contribute to molecular memory clocks.
• Findings offer insights for designing optimized training protocols for memory enhancement and maintenance.