Fig. 9

Potentially Toll-like receptor signaling cascade in Aplysia californica. Based upon conservation of key components of the vertebrates TOLL-like receptor (TLR) cascade and conserved function of those components in other mollusks, we propose a vertebrate-like TLR signaling cascade in Aplysia californica. The Aplysia genome encodes putative orthologs of all major components of the classical TLR singaling cascade, including a diversity of TLRs, adapter protein MyD88, two MyD88 interacting IRAKs, E3 ligases and scaffolding protein, E3 ligase Pellino, E3 ligase LUBAC complex comprised of HOIP, HOIL1, and SHARPIN, the Tak1 kinase complex comprising of TAB1, TAB2/3, and TAK1, the IkB Kinase (IKK) complex made up of IKKa, IKKb, and IKKg/NEMO, several MAP kinases, and transcription factors in the NFkB, interferon regulatory factor (IRF), and AP-1 family. The Aplysia genome also encodes for elements of non-canonical TLR/NFkB singaling including TRAF3, non-canoninical IKK TABK1 and associated adapter NAP1. A broad suit of non-Myd88 TIR domain containing proteins suggests a diverse suit of alternative TLR signaling cascades that have yet to be described