Yasui et al. 45 generated Pkn1-knockout (KO) mice that display an appearance comparable to that of the control and do not exhibit defects in lymphocyte development within 12 weeks of age; however, germinal centers (GCs) form spontaneously in the spleen at >30 weeks of age, even in the absence of immunization or infection, showing an autoimmune-like disease characterized by autoantibody production and glomerulonephritis. Here, PKN1 is linked to glomerulonephritis.