Adaptor-related protein complex 3 subunit sigma-1 (AP3S1)

Adaptor-related protein complex 3 subunit sigma-1 (AP3S1) is a subunit of the heterotetrameric adaptor protein complex 3 (AP-3), which is crucial for the formation and trafficking of subcellular vesicles budded from the Golgi apparatus. AP3S1 is essential for assembling AP-3 and mediates the sorting of membrane proteins destined for endosomes, lysosomes, and specialized organelles such as melanosomes and secretory vesicles. It recognizes dileucine-based sorting signals on cargo, facilitating accurate cargo delivery to lysosome-related organelles and ensuring cellular homeostasis. Dysregulation or mutations in AP3S1 have been implicated in cancer (e.g., cervical tumors, colorectal cancers), metabolic disorders (linked to insulin receptor signaling in diabetes), pigmentation defects, and certain neurological and lymphoproliferative diseases. AP3S1 is not currently established as a direct therapeutic target or known receptor, enzyme, transporter, or ion channel. It is primarily classified as a component of intracellular trafficking machinery and has emerging research interest for its roles in disease, but currently lacks approved drug modulators or direct disease-modifying therapies targeting it.

Other names

AP-3 complex subunit sigma-1AP3S1CLAPS3Sigma3A-adaptinAP-3 complex subunit sigma-3AAdaptor-related protein complex 3 subunit sigma-1Sigma-3A-adaptinSigma-adaptin 3aClathrin-associated/assembly/adaptor protein, small 3Clathrin-associated/assembly/adapter protein, small 3 (22kD)Adaptor related protein complex 3 sigma 1 subunitAP3S1_HUMANAP3S1 gene