This study identifies Drosophila TMEM63 (DmTMEM63) as a lysosomal mechanosensitive ion channel that mediates mechanosensitivity and regulates lysosomal morphology and function. DmTMEM63 localizes to lysosomes and is essential for maintaining lysosomal homeostasis. Tmem63 mutant flies exhibit impaired lysosomal degradation, synaptic loss, progressive motor deficits, and early death, with some phenotypes resembling those of human TMEM63-associated diseases. Mouse TMEM63A also mediates lysosomal mechanosensitivity in Neuro-2a cells, indicating functional conservation between mammals and Drosophila. The findings reveal that DmTMEM63 functions as a lysosomal mechanosensor and provide insights into the physiological roles of mechanosensing in subcellular organelles. The study also demonstrates that DmTMEM63 is involved in lysosomal remodeling, with its expression levels affecting lysosomal morphology. Furthermore, Tmem63 mutant flies display progressive motor deficits and synaptic loss, suggesting a role for lysosomal dysfunction in TMEM63-related diseases. The study highlights the importance of lysosomal mechanosensing in maintaining cellular homeostasis and provides a molecular basis for understanding the mechanosensitive process in subcellular organelles. The results suggest that TMEM63 proteins are conserved across species and play a critical role in lysosomal function and homeostasis. The study also identifies a pathogenic mutation in TMEM63 that leads to mislocalization of the protein and impaired function, highlighting the importance of proper protein localization for normal cellular function. Overall, the study provides new insights into the role of TMEM63 in lysosomal mechanosensing and its physiological functions in vivo.This study identifies Drosophila TMEM63 (DmTMEM63) as a lysosomal mechanosensitive ion channel that mediates mechanosensitivity and regulates lysosomal morphology and function. DmTMEM63 localizes to lysosomes and is essential for maintaining lysosomal homeostasis. Tmem63 mutant flies exhibit impaired lysosomal degradation, synaptic loss, progressive motor deficits, and early death, with some phenotypes resembling those of human TMEM63-associated diseases. Mouse TMEM63A also mediates lysosomal mechanosensitivity in Neuro-2a cells, indicating functional conservation between mammals and Drosophila. The findings reveal that DmTMEM63 functions as a lysosomal mechanosensor and provide insights into the physiological roles of mechanosensing in subcellular organelles. The study also demonstrates that DmTMEM63 is involved in lysosomal remodeling, with its expression levels affecting lysosomal morphology. Furthermore, Tmem63 mutant flies display progressive motor deficits and synaptic loss, suggesting a role for lysosomal dysfunction in TMEM63-related diseases. The study highlights the importance of lysosomal mechanosensing in maintaining cellular homeostasis and provides a molecular basis for understanding the mechanosensitive process in subcellular organelles. The results suggest that TMEM63 proteins are conserved across species and play a critical role in lysosomal function and homeostasis. The study also identifies a pathogenic mutation in TMEM63 that leads to mislocalization of the protein and impaired function, highlighting the importance of proper protein localization for normal cellular function. Overall, the study provides new insights into the role of TMEM63 in lysosomal mechanosensing and its physiological functions in vivo.