Multifunctional effector that can suppress host BAK1/SERK3-mediated immunity through at least two different pathways (PubMed:19794118, PubMed:20457921, PubMed:21348873, PubMed:26348328). Manipulates plant immunity by targeting and stabilizing host E3 ligase CMPG1. Preventing the normal 26S proteasome-dependent degradation of potato CMPG1, and thus potentially of its protein substrates in the host cell, further abolishes host cell death during the biotrophic phase of infection (PubMed:19794118, PubMed:20457921, PubMed:21348873). Associates also with the dynamin-related protein 2 (DRP2), a plant GTPase involved in immune receptor-mediated endocytosis (PubMed:26348328). The Avr3A(KI) form is recognized by R3a which triggers R3a-mediated hypersensitivity and suppresses INF1-induced cell death (PubMed:15894622, PubMed:16965554, PubMed:19245321). Forms homodimers via the RxLR-dEER motif (PubMed:22977236, PubMed:28522546). Interacts with host E3 ligase CMPG1 (PubMed:20457921). Interacts with host DRP2 (PubMed:26348328). Avr3A(KI), but not Avr3A(EM), is relocalized to endosomes in the presence of R3a. Expression is induced during host plant infection. The RxLR-dEER motif is required for the delivery of the effector to the host cell cytoplasm but does not bind phosphatidylinositol monophosphates (PubMed:17914356, PubMed:22977236, PubMed:21821794). The motif is cleaved after the RxLR sequence (PubMed:28522546). The RxLR motif (residues 44 to 47) plays a crucial role in the intracellular processing before secretion (PubMed:28522546). The Glu-rich part localized just after the cleavage site (residues 48 to 59) is required for homodimerization (PubMed:28522546). The conserved, positively charged effector domain (residues 77 to 147), rather than the RXLR domain, is required for binding to phosphatidylinositol monophosphates (PIPs). PIP binding is necessary for accumulation of CMPG1 and Avr3a in host plants. Proteolytically cleaved. The cleavage site directly after the RxLR sequence and the high conservation among other effector proteins suggest that the RxLR motif might play a crucial role in the intracellular processing before secretion. glycosylated. N-acetylated at Lys-48 after cleavage. The AVR3a protein of Phytophthora infestans is a polymorphic member of the RXLR class of cytoplasmic effectors with dual functions. Avr3A(KI) but not Avr3a(EM) activates innate immunity triggered by the potato resistance protein R3a and is a strong suppressor of the cell-death response induced by INF1 elicitin, a secreted P.infestans protein that has features of pathogen-associated molecular patterns. The 2 polymorphic residues between AVR3a(KI) and Avr3a(EM) are localized at positions 80 and 103, respectively. Belongs to the RxLR effector family.