P-type ATPase involved in specific uptake of calcium. Essential for growth and maintenance of cell surface integrity under Ca(2+)-deficient conditions. ATP + Ca(2+)(in) + H2O = ADP + Ca(2+)(out) + H(+) + phosphate Expression is negatively regulated by Ca(2+). Disruption of the gene leads to impaired growth under Ca(2+)-deficient conditions. Mutant also shows hypersensitivity to polymyxin B, increased biofilm formation and higher cell aggregation, indicating cell envelope defects. Belongs to the cation transport ATPase (P-type) (TC 3.A.3) family.