\n PTM:Phosphorylated upon DNA damage, probably by ATM or ATR. Contains 1 UBA domain. Contains 1 ubiquitin-like domain. subcellular location:May associate with the endoplasmic reticulum. subunit:Homodimer. Binds SCA1. Binds signal sequences of proteins that are targeted to the endoplasmic reticulum. tissue specificity:Highly expressed in pancreas, kidney, skeletal muscle, heart and throughout the brain, and at lower levels in placenta, lung and liver.