Type 3 Secretion System (IMAGE) Massachusetts General Hospital Caption Type 3 secretion systems (T3SSs) are used by several pathogenic bacterial species to deliver effector proteins, responsible for the effects of infection, into the target host cells. An MGH research team has discovered that interaction between structural proteins within the host cell called intermediate filaments and IpaC, a bacterial protein that forms the pore through the host cell membrane, is required for T3SSs to dock onto the pores and secrete effector proteins into the host cell. Credit (Goldberg Laboratory, Division of Infectious Diseases, Massachusetts General Hospital) Usage Restrictions For use only in conjunction with coverage of this study. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.