Effector that enhances plant susceptibility to P.parasitica in Nicotiana benthamiana and Arabidopsis thaliana. Triggers non-specific cell death in a variety of plants, including tobacco, tomato, potato and A.thaliana. E4-induced cell death is dependent on HSP90, NPK and SGT1, suggesting that PpE4 is recognized by the plant immune system. Accumulates around haustoria during plant infection. Expression is highly induced during the early stages of infection. The RxLR-dEER motif acts to carry the protein into the host cell cytoplasm through binding to cell surface phosphatidylinositol-3-phosphate. Results in significantly reduced virulence on Nicotiana benthamiana. Belongs to the RxLR effector family.