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<\/p>\nWhat makes you remember a favorite vacation \u2014 the smell of the ocean, the taste of new foods \u2014 but forget where you left your keys? Inside the brain, the answer comes down to a carefully timed chemical choreography.<\/p>\n
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Leterrier, NeuroCyto Lab, via NIH Flickr<\/p>\n
The chemical basis of memory occurs in neurons, shown here, with a calcium spark, calmodulin translation and CaMKII reinforcement.<\/p>\n
At its core, memory is biochemical. The brain\u2019s ability to receive, store and recall information relies on ions, proteins and signaling pathways acting in concert to convert electrical activity into chemical changes at synapses and within neurons.<\/p>\n
When this choreography falters, the consequences can be profound. Memory disruption underlies disorders such as Alzheimer\u2019s disease, age-related cognitive decline and learning disabilities.<\/p>\n
Among the key players in this molecular ensemble are calcium ions, known as Ca\u00b2\u207a, the calcium-binding protein calmodulin, or CaM, and calcium and calmodulin-dependent kinase II, or CaMKII. Together, they form a signaling axis that drives the cellular changes required to form and maintain memories.<\/p>\n
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A.J. Robison<\/p>\n
Neuroscientist A.J. Robison<\/a>, professor in the department of physiology at Michigan State University, describes this signaling axis as fundamental to memory formation.<\/p>\n \u201cWe’ve known for more than 30 years that calmodulin functions as a calcium sensor and drives the activity of downstream signaling cascades, including CaMKII,\u201d Robison said. \u201cThis activity is essential for the cellular correlates of learning, like long-term potentiation and long-term depression, and for actual learning itself in mice and other models.\u201d<\/p>\n Yet this process is complex. Knowing the players is not the same as understanding the performance. \u00a0Many questions remain about how these chemical changes produce lasting synaptic effects that support memories over days, years or even a lifetime.<\/p>\n Understanding these mechanisms advances basic neuroscience and points to potential therapeutic targets for disorders that impair learning, cognition and memory. Recent research published in American Society for Biochemistry and Molecular Biology journals is helping to clarify this signaling network, revealing new layers of regulation \u2014 and unexpected opportunities for intervention.<\/p>\n Calcium: A chemical spark<\/p>\n Courtney Chandler<\/p>\n Calcium signaling links neuronal activity to memory formation and learning. Calcium (Ca\u00b2\u207a) influx triggers calmodulin (CaM) activation, which engages CaMKII to drive synaptic changes that support learning and long-term memory.<\/p>\n Every memory begins with a surge. Sensory inputs trigger rapid electrical spikes, called action potentials, that race along neurons and cause neurotransmitter release. Activation of the neurotransmitter receptors causes calcium ions to flood into the cell, acting as a spark for downstream signaling.<\/p>\n Repeated calcium surges signal that something worth remembering may be happening. Recurrent rises in intracellular calcium trigger long-term potentiation, a sustained strengthening of synaptic connections widely regarded as a hallmark of memory formation. Over time, these connections embed patterns of activity that encode memories.<\/p>\n Chiho Sugimoto, a postdoctoral fellow at Vanderbilt University who earned her Ph.D. in Robison\u2019s lab, said this initial calcium spark is key to triggering the molecular cascade that underpins memory and learning. While calcium does not store memory itself, it sets the conditions that allow memories to form.<\/p>\n \u201cCalcium is essential to how neurons communicate with each other by regulating the release of neurotransmitters and the strength of synapses, which are critical factors for learning and memory,\u201d she said. \u201cCalcium can control the timing, location and magnitude of synaptic signals through pathways such as CaM\u2013CaMKII, which can shape neuronal circuits, synaptic plasticity and gene expression, the key drivers of brain function.\u201d<\/p>\n Chiho Sugimoto<\/p>\n A study published in the Journal of Biological Chemistry shows just how finely tuned<\/a> that control can be. Using patch-clamp electrophysiology, a technique that measures electrical currents through specific ion channels, researchers studied voltage-gated ion channel activity in neurons. They focused on how retinoic acid, a vitamin A metabolite known to influence neural plasticity, modulates ion channel activity and synaptic function.<\/p>\n Researchers found that retinoic acid modulates neuronal firing by inhibiting potassium channels involved in repolarization and limiting calcium channel activation. By coordinating multiple ion channel targets, retinoic acid fine-tunes calcium entry into neurons, shaping neurotransmitter release and plasticity-related gene expression.<\/p>\n Vitamin A deficiency has been linked to cognitive impairments, highlighting how memory and nutrition may be connected. This work may help clarify how dietary or pharmacological interventions could support healthy brain function.<\/p>\n Calmodulin: The translator of calcium signals<\/p>\n A calcium pulse is only meaningful if the cell can understand it. This translation falls to CaM, which functions as calcium\u2019s interpreter.<\/p>\n Once activated by Ca2+ (red), the protein calmodulin (blue) interacts with downstream targets to influence synaptic plasticity, impacting learning and memory.<\/p>\n When calcium binds, CaM undergoes structural rearrangements that enable it to activate downstream enzymes, including CaMKII. In this way, CaM helps determine how neurons respond to activity patterns associated with learning, distinguishing background noise from signals strong enough to promote synaptic change.<\/p>\n CaM is not simply waiting for calcium to bind. CaM itself can also be chemically modified, and these posttranslational modifications can alter its activity and influence synaptic plasticity. Sugimoto said this layer of regulation may be critical for learning.<\/p>\n \u201cCaM\u2013CaMKII signaling is impacted by a variety of posttranslational modifications,\u201d she said. \u201cThe discovery (of new CaM modifications would) add critical detail to our model of calcium effects on neuronal activity and synaptic strength.\u201d<\/p>\n To this end, two complementary studies published in JBC highlighted the importance of a newly identified modification: acetylation.<\/p>\n One study identified acetylation as a novel CaM modification<\/a> and found that it is more prevalent during active learning. Mice engineered to carry a form of CaM that could not be acetylated showed reduced learning and weaker fear-related memory. A second study identified SRC3 as the enzyme responsible for CaM acetylation<\/a>. When SRC3 was blocked in mice, the animals had difficulty strengthening synaptic connections and showed weaker fear-based learning.<\/p>\n The neurotransmitter glutamate is transported by synaptic vesicles to the presynaptic membrane. Calcium channels trigger the neurotransmitter release into the inter synaptic cleft. Glutamate binds to the NMDA (left) and AMPA receptors allowing calcium ions (yellow) to pass the postsynaptic membrane. This starts an action potential.<\/p>\n Together, the studies suggest that CaM acetylation plays an important role in synaptic plasticity and learning, acting as a regulatory layer that links neural activity to memory formation. The findings suggest that targeting CaM modifications such as acetylation could offer new strategies for preserving or restoring learning and memory in disease.<\/p>\n Sugimoto and Robison co-authored a commentary emphasizing the significance of these findings<\/a>.<\/p>\n \u201cWhat’s novel about this is the discovery that calmodulin posttranslational modifications can drive differences in the activation of downstream pathways,\u201d Robison said. \u201cThese studies help model how modification of calmodulin at these residues can drive differences in learning.\u201d<\/p>\n Robison also emphasized the potential clinical implications of the findings.<\/p>\n \u201cThe SRC3 pathway could represent a (promising) approach to targeting CaM function in hippocampal neurons and may represent a novel pathway for therapeutic intervention in diseases of cognition, like Alzheimer\u2019s or cognitive disabilities,\u201d he said.<\/p>\n CaMKII: The molecular engine of memory<\/p>\n If calcium provides the spark and CaM interprets the signal, CaMKII does the heavy lifting. Once activated by calcium-bound CaM, CaMKII phosphorylates key synaptic proteins, reinforcing the connections that encode memory.<\/p>\n 3D reconstruction of the human calcium\/calmodulin-dependent protein kinase molecule.<\/p>\n CaMKII has long been recognized as central to learning. However, precisely because of this central role, the enzyme has been viewed as an untouchable due to concerns that targeting it therapeutically could disrupt or erase established memories.<\/p>\n Recent studies published in JBC are beginning to address this uncertainty.<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/04\/480-Calcium-Image.jpg\"\/)
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