The supplementary materials for the study "A mechanism of lysosomal calcium entry" provide detailed information on the localization and function of the human lysosomal calcium importer (LCI). The study shows that human LCI is primarily localized to the Golgi in HeLa cells, but also detected on lysosomal membranes, suggesting a potential role in lysosomal calcium transport. However, the low lysosome localization does not preclude a physiological role for human LCI on the lysosome membrane. The study also reports that human LCI significantly increases lysosomal calcium levels in worms, but the measurements are underestimated due to the limitations of the CalipHluor2.0 probe. The study further shows that human LCI mutants, such as G304R, E108A, and E248A, can lead to high lysosomal calcium levels in lci-1(+/-) worms, but these mutants impair lysosomal calcium import in other assays. This suggests that human LCI functions as a dimer, with the remaining copy of endogenous worm lci-1 dimerizing with the mutant human LCI to form a partially functional transporter. The study also shows that human LCI shares homology with vcx1, a protein involved in calcium transport, and that human LCI may function similarly in response to high cytosolic calcium. The study further shows that human LCI rescues vacuolar dysfunction in K665 yeast strains, suggesting a role in vacuolar function. The study also includes detailed figures and tables showing the localization of human LCI, its function in rescuing organism and cellular phenotypes, and its role in lysosomal calcium transport. The study also includes references to other studies on calcium transport and lysosomal function.The supplementary materials for the study "A mechanism of lysosomal calcium entry" provide detailed information on the localization and function of the human lysosomal calcium importer (LCI). The study shows that human LCI is primarily localized to the Golgi in HeLa cells, but also detected on lysosomal membranes, suggesting a potential role in lysosomal calcium transport. However, the low lysosome localization does not preclude a physiological role for human LCI on the lysosome membrane. The study also reports that human LCI significantly increases lysosomal calcium levels in worms, but the measurements are underestimated due to the limitations of the CalipHluor2.0 probe. The study further shows that human LCI mutants, such as G304R, E108A, and E248A, can lead to high lysosomal calcium levels in lci-1(+/-) worms, but these mutants impair lysosomal calcium import in other assays. This suggests that human LCI functions as a dimer, with the remaining copy of endogenous worm lci-1 dimerizing with the mutant human LCI to form a partially functional transporter. The study also shows that human LCI shares homology with vcx1, a protein involved in calcium transport, and that human LCI may function similarly in response to high cytosolic calcium. The study further shows that human LCI rescues vacuolar dysfunction in K665 yeast strains, suggesting a role in vacuolar function. The study also includes detailed figures and tables showing the localization of human LCI, its function in rescuing organism and cellular phenotypes, and its role in lysosomal calcium transport. The study also includes references to other studies on calcium transport and lysosomal function.