N-methyl-D-aspartate receptor polyamine site (NMDAR polyamine site)

The polyamine binding site refers to specific regulatory regions on the N-methyl-D-aspartate (NMDA) receptor and inwardly rectifying potassium (Kir) channels that interact with endogenous polyamines such as spermine and spermidine [7, 8]. On the NMDA receptor, these sites act as allosteric modulators; at low concentrations, polyamines enhance receptor activity by increasing the affinity for glycine and the frequency of channel opening, while at higher concentrations, they can exert an inhibitory effect [10, 11]. In Kir channels, polyamines function as intracellular pore blockers, providing the molecular basis for inward rectification by obstructing the channel at depolarized membrane potentials [3, 15]. These sites are critical for regulating synaptic plasticity and neuronal excitability, and their dysregulation is implicated in neurodegenerative diseases, stroke, and chronic pain [1, 21]. Pharmacological agents targeting these sites, such as the antagonist arcaine or the NR2B-selective modulator ifenprodil, are investigated for their neuroprotective potential and ability to mitigate excitotoxicity [10, 11]. Additionally, the elevated polyamine levels observed in many cancers make these binding sites and the associated transport systems potential targets for oncological interventions [2, 13]. Recent research has also identified potential polyamine binding pockets in viral proteins like the SARS-CoV-2 ORF3a, suggesting a role in viral-host interactions [16].

Other names

Polyamine binding siteNMDA receptor polyamine siteSpermine binding siteSpermidine binding sitePolyamine regulatory siteKir channel polyamine block site

Allosteric modulation of NMDA receptor activity and voltage-dependent pore blockade of inwardly rectifying potassium channels.