Enables peptidase activity. Involved in several processes, including cellular response to unfolded protein; membrane protein proteolysis; and positive regulation of protein processing. Located in endoplasmic reticulum membrane and endoplasmic reticulum quality control compartment. Is integral component of endoplasmic reticulum membrane. Orthologous to human RHBDD1 (rhomboid domain containing 1). [provided by Alliance of Genome Resources, Apr 2022]