Enables calcium ion binding activity. Involved in several processes, including regulation of sequestering of calcium ion; response to denervation involved in regulation of muscle adaptation; and skeletal muscle tissue development. Located in I band; T-tubule; and terminal cisterna lumen. Colocalizes with Golgi apparatus. Human ortholog(s) of this gene implicated in type 2 diabetes mellitus. Orthologous to human CASQ1 (calsequestrin 1). [provided by Alliance of Genome Resources, Apr 2022]