Intramembrane-cleaving aspartic protease (I-CLiP) that cleaves type II membrane signal peptides in the hydrophobic plane of the membrane (By similarity). Catalyzes intramembrane proteolysis of some signal peptides after they have been cleaved from a preprotein, resulting in the release of the fragment from the ER membrane into the cytoplasm (By similarity). Plays a critical role in the development and function of the reproductive tissues, especially in pollen development. Ubiquitous with the highest expression in emerging leaves, roots, and floral tissues (at the protein level). Highly detected in pollen. Expressed in the shoot meristem and root epidermal cells in germinating seeds. At the reproductive stage, expressed in the whole shoot apex. The first transmembrane domain may act as a type I signal anchor. The PAL motif is required for normal active site conformation. Mostly lethal due to a male gametophytic defect. Belongs to the peptidase A22B family.