TAMALIN (trafficking regulator and scaffold protein tamalin) is a postsynaptic PDZ-scaffold protein that regulates intracellular trafficking and synaptic organization of group 1 metabotropic glutamate receptors (mGluRs) 1. The protein contains multiple protein-interacting domains including a PDZ domain, leucine-zipper region, and C-terminal PDZ binding motif, enabling assembly of multi-protein complexes 1. TAMALIN mediates ligand-dependent internalization of mGluR1 and mGluR5 through interactions with S-SCAM and regulates mGluR-dependent synaptic plasticity 2. Beyond mGluR regulation, TAMALIN participates in ARF1/ARF6-mediated trafficking during hepatocyte growth factor signaling, coordinating membrane trafficking of the Rac1-GEF Dock180 3. In neurons, TAMALIN promotes dendritic outgrowth and arborization via EFA6A/Arf6 signaling and cytoskeleton dynamics 4. Dysregulation of TAMALIN is implicated in schizophrenia pathology; postmortem brain studies show reduced TAMALIN protein levels in dorsolateral prefrontal cortex and increased levels in hippocampal CA1, correlating with altered mGluR5 regulation 5 6. Additionally, TAMALIN DNA methylation is hypermethylated in prostate cancer tissues and represents a potential diagnostic biomarker 7.