CLDN24 (claudin 24) is a four-transmembrane protein belonging to the claudin family that plays dual roles in cellular adhesion and synaptic neurotransmission. Structurally, CLDN24 shares the characteristic four-transmembrane domain topology conserved across the claudin family 1, positioning it within the PMP-22/EMP/MP20/claudin superfamily 2. As a tight junction protein, CLDN24 contributes to calcium-independent cell adhesion and intercellular space obliteration, consistent with canonical claudin functions. Beyond this classical role, CLDN24 functions as a novel auxiliary subunit of AMPA receptors (AMPARs) in cerebellar granule cells, specifically enhancing AMPAR fidelity by accelerating recovery of desensitized receptors 2. This mechanism counterbalances gating modulation mediated by TARP-γ2 and GSG1L, enabling rapid receptor reactivation and enhancing fast excitatory neurotransmission in the mammalian central nervous system 2. CLDN24 is located on human chromosome 4 1. The gene's expression pattern and chr4 localization within a commonly deleted region in malignant melanoma suggest potential tumor suppressor implications 3, though clinical significance remains to be fully elucidated.