TRAK1 (trafficking kinesin protein 1) is a mitochondrial adapter protein essential for neuronal function and development. Primary Function: TRAK1 serves as a core scaffold linking mitochondria to the microtubule transport machinery. It directly interacts with MIRO1 on the outer mitochondrial membrane and recruits kinesin-1 and dynein-dynactin motors to enable anterograde and retrograde mitochondrial transport along axons 12. Additionally, TRAK1 regulates endosome-to-lysosome trafficking, including EGFR and GABA-A receptor internalization [PMID:18675823 via UniProt]. Mechanism: TRAK1 forms a dimeric complex with MIRO1 through two distinct binding sites, independent of calcium or nucleotide conditions 2. It also interacts with mitofusins to promote mitochondrial tethering and fusion 3, and associates with DISC1 interactors NDE1 and GSK3β to regulate axonal mitochondrial motility 4. Disease Relevance: Homozygous truncating TRAK1 variants cause developmental and epileptic encephalopathy 68, manifesting as severe neurodegeneration with defective mitochondrial distribution, reduced membrane potential, and impaired respiration 5. Variants are also linked to childhood absence epilepsy and intellectual disability 6. Clinical Significance: TRAK1 dysfunction impairs critical mitochondrial delivery to high-energy neuronal sites, contributing to neurodegeneration; enhancing TRAK1-mediated mitochondrial transport shows neuroprotective potential in ischemic stroke 78.