Figure 7.

Role of Synoviolin/Hrd1 in collagen-induced arthritis. Immunization using type II collagen evokes immunological processes followed by production of anti-type II collagen antibodies, which are thought to result in joint inflammation. Activated macrophages secrete cytokines, such as TNFα and IL-1β, which stimulate synovial cell proliferation. Because both antibody and cytokine productions are not impaired in syno^+/-, it is conceivable that Synoviolin/Hrd1 is involved in synovial cell overgrowth. Our results indicate that Synoviolin/Hrd1 regulates the activity of ERAD system and, consequently, controls synovial cell apoptosis.