In memoriam: John Lisman - commentaries on CaMKII as a memory molecule

Area of Science:

• Neuroscience
• Molecular Biology
• Memory Research

Background:

• John Lisman's posthumously published review addresses the molecular underpinnings of the engram, the physical trace of memory.
• The review focuses on two key molecules: calcium-calmodulin-dependent protein kinase II (CaMKII) and protein kinase M zeta (PKMζ).
• Lisman's work was published as submitted due to his untimely death, prompting a series of commentaries.

Purpose of the Study:

• To critically evaluate the criteria for identifying the molecular basis of the memory engram.
• To present and discuss John Lisman's final perspectives on CaMKII and PKMζ in memory.
• To provide context and commentary on Lisman's review, alongside a separate response from other researchers.

Main Methods:

• Review and commentary on existing literature regarding molecular mechanisms of memory.
• Analysis of proposed molecular candidates, specifically CaMKII and PKMζ, for engram formation and maintenance.
• Discussion of criteria for establishing molecular causality in memory processes.

Main Results:

• The publication presents Lisman's criteria for identifying molecular components of the engram.
• Commentaries offer diverse perspectives on the roles of CaMKII and PKMζ in memory.
• A separate article by Sacktor and Fenton presents evidence for PKMζ as a key memory molecule.

Conclusions:

• The engram's molecular basis remains a subject of active investigation and debate.
• Established criteria are crucial for validating molecular candidates involved in memory.
• Further research is needed to definitively determine the roles of CaMKII and PKMζ in memory persistence.