Plays a role in cuticle calcification. May induce precipitation of the calcium stored in the posterior caeca as calcium carbonate. During the premolt period, localizes to microvilli-rich apical regions and to the subnuclear region. During the postmolt period, localizes to the intercellular space, basal region of cells and calcium reabsorption spherules. Posterior caeca epithelium of the gut. Expression is detected at the start of the premolt period and accumulates during this period from D1'b to D3. After ecdysis, expressed in the postmolt period but at much lower levels. Not detected in the intermolt period. Indirectly by 20-hydroxyecdysone. Phosphorylated on Ser and Tyr residues. Calcium-binding activity is dependent on serine phosphorylation but not on tyrosine phosphorylation. Binds calcium. N-terminal sequence obtained in PubMed:8620040 was later shown to be incomplete at the N-terminus.