Inner membrane component of the type II secretion system required for the energy-dependent secretion of extracellular factors such as proteases and toxins from the periplasm. Plays a role in the complex assembly and recruits OutM resulting in a stable complex in the inner membrane. Provides thus a link between the energy-providing OutE protein in the cytoplasm and the rest of the T2SS machinery. Type II secretion system is composed of four main components: the outer membrane complex, the inner membrane complex, the cytoplasmic secretion ATPase and the periplasm-spanning pseudopilus (By similarity). Forms homodimers. Interacts with OutM/GspM. Interacts with OutE/GspE and OutF/GspF (By similarity). Belongs to the GSP L family.