Specifically hydroxylates an Asp or Asn residue in certain epidermal growth factor-like (EGF) domains of a number of proteins. Membrane-bound Ca(2+)-sensing protein, which is a structural component of the ER-plasma membrane junctions. Isoform 8 regulates the activity of Ca(+2) released-activated Ca(+2) (CRAC) channels in T-cells. 2-oxoglutarate + L-aspartyl-[protein] + O2 = 3-hydroxy-L-aspartyl-[protein] + CO2 + succinate Monomer (By similarity). Isoform 8 interacts with ORAI1 and STIM1. Isoform 4 interacts with CASQ2. Comment: 3 functionally distinct proteins are produced by alternative splicing: Aspartyl/asparaginyl beta-hydroxylase, Junctin and Junctate. Additional isoforms are produced by alternative splicing. Isoform 1 is detected in all tissues tested. Isoform 8 is mainly expressed in pancreas, heart, brain, kidney and liver. Isoform 8 is expressed in kidney (at protein level). The disease is caused by variants affecting the gene represented in this entry. Belongs to the aspartyl/asparaginyl beta-hydroxylase family.