Fig. 4

Neighbor Joining Tree of putative Aplysia Toll-like Receptor TLR domains. Neighbor joining tree generated using the Jones-Taylor-Thornton model and bootstrapped with 1000 iterations (see Methods) using the TIR domains of the longest protein isoform of all putative Aplysia TLR genes. Corresponding orthogroups identified in OrthoFinder analysis demarcate member proteins with strips and orthogroup identifier. Heatmap to the right of the tree represents presences (black square) or absence (light grey square) of key protein domains identified by InterProScan. Domain category is demarcated with a strip above the heatmap columns. Domains without a category include SP (signal peptide, Phobius), TIR (Toll-interleukin Receptor homology domain, IPR000157), TM (transmembrane domain, Phobius). Domains demarcated as LRRs represent various leucine-rich repeat subtypes: LRR1 (single LRR, IPR001611), T (typical type, IPR003591, SM00369), S (bacterial type, SM00364), SD22 (sds22-like, SM00365), BspA (BspA type, IPR026906), RI (Ribonuclease inhibitor, G3DSA:3.80.10.10), and CT (Cysteine-rich c-terminal flanking region of LRR, IPR000483, SM00082). Domains demarcated as “Novel Domains” represent domains found in Aplysia TLRs not typically associated with vertebrate TLRS, including MBT (malignant brain tumor repeat, IPR004092), ROC (Ras of complex small GTPase domain, IPR020859), COR (C-terminal of ROC, IPR032171), and EF (EF-hand, IPR002048). Only the TIR domains of XP_012942443.2 and XP_005112480.1 do not cluster with their Orthogroup. The TLRS contain Roc and Cor (ROCO) domains as well as other accessory domains, suggesting possible novel function. Only two TLRs contain c-terminal flanking regions