MAP1S (microtubule-associated protein 1S) is a multifunctional protein that plays crucial roles in autophagy regulation and microtubule dynamics. MAP1S serves as a key autophagy activator by interacting with LC3 and promoting autophagosomal biogenesis and degradation 1. The protein bridges autophagic components with microtubules and mitochondria, facilitating proper autophagy flux 1. MAP1S stability is regulated through interaction with histone deacetylases, particularly HDAC4 and HDAC6 23. Functionally, MAP1S promotes the degradation of extracellular matrix proteins like fibronectin, preventing tissue fibrosis 42. MAP1S deficiency leads to severe pathological consequences, including reduced lifespan, liver and renal fibrosis, and hepatocellular carcinoma development 24. The protein also regulates microtubule dynamics through interactions with α-tubulin arginylation, modulating microtubule growth rate and stability 5. In cancer contexts, MAP1S can be upregulated by viral proteins like HBx, promoting tumor proliferation and migration through TGF-β signaling pathways 3. Additionally, MAP1S expression is regulated by PU.1 during neutrophil differentiation and is associated with various neurodegenerative diseases 67.