PHILADELPHIA (March 11, 2019) — Adhesion of lymphocytes to their cellular targets is critical to adaptive immunity, the body’s ability to assign specific antibodies to pathogens. This process is controlled by a group of cell surface receptors called integrins through a cascade of molecular events known as inside-out signaling. This pathway is regulated by a small GTPase closely related to the RAS oncogene called RAP1.
Jinhua Wu, PhD, associate professor in the Molecular Therapeutics Program at Fox Chase Cancer Center, has found that the RAP1 function can be suppressed if its effector protein (RIAM) adopts an autoinhibitory configuration, and this suppression of RAP1 function is released once RIAM is phosphorylated. This result reveals the first example of a novel regulatory mechanism by which an effector protein is autoinhibited, thus offering a new strategy for the identification of novel targets to better treat autoimmune diseases associated with RAP1 and integrin.
Wu’s lab focuses on understanding the structural basis of intermolecular complexes and intramolecular rearrangements that control integrin-mediated cell adhesion and motility. Their aim is to enable the development of next-generation inhibitors by mapping the structural details of each signaling event involved in this pathway.
The paper, entitled, “Molecular basis for autoinhibition of RIAM regulated by FAK in integrin activation,” appears in Proceedings of the National Academy of Sciences.
This work was supported by grants GM119560 and CA163489 from the National Institutes of Health, 4100068716 from the Pennsylvania Department of Health, RSG-15-167-01-DMC from the American Cancer Society, and Pilot Project Award 5P30CA006927-51 made possible with a portion of the Cancer Center Support Grant.