GRIK3 encodes a kainate-selective ionotropic glutamate receptor that functions as a ligand-gated cation channel. Upon L-glutamate binding, GRIK3 undergoes conformational changes to open its ion channel, converting chemical signals to electrical impulses before rapidly desensitizing 1. In the central nervous system, GRIK3 plays critical roles in synaptic transmission and plasticity essential for learning and memory 2. Developmentally, GRIK3 shows transient expression on rod precursors within the retina, where it detects light-dependent glutamate released from intrinsically photosensitive retinal ganglion cells, controlling developmental rod apoptosis 3. GRIK3 haploinsufficiency causes severe developmental delay affecting language and fine motor skills 2, while genetic variants associate with recurrent major depressive disorder through preferential maternal transmission 4. Beyond neurodevelopmental functions, GRIK3 has pathological roles in cancer. Aberrant GRIK3 expression in pediatric pilocytic astrocytomas couples with glutamate signaling to activate Src-mediated PDGF receptor signaling and ERK-dependent proliferation 5. In gastric and colorectal cancers, elevated GRIK3 expression correlates with poor prognosis, lymph node metastasis, and TNM stage advancement, with GRIK3 serving as an independent prognostic biomarker 67. These findings establish GRIK3 as both a neurodevelopmental protein and emerging oncogenic target.