Other MGCs point to galectins, I type lectins able to bind carbohydrate ligands via immunoglobulin like domains, selleckbio GH18 chitinase enzymes, L type lectins entailed in the intracellular protein sorting and P type lectins, transmembrane proteins involved in the transport of lysosomal enzymes from the Golgi complex and the cell surface to lysosomes. For instance, chitinases are glycosyl hydrolases widely expressed from cnidarians to mammals, able to degrade the polysaccharide b poly N acetyl D glucosamine and confer protection against chitin containing pathogens and parasites. Mytibase is also rich in sequences with WD 40 repeats and Leucin Rich Repeats.

The modular organization of WD and LRR domains of vertebrate proteins sustains the diversity and plasticity of the apoptosome and inflammasome complexes in response to microbial products and metabolic stress, with the latter commonly signalled by ROS, nucleic acids, cathepsin and other molecules released by damaged cells. In detail, the ligand binding to the carboxy terminal LRR region of cytosolic receptors of the NOD like family can trigger receptor clustering, recruitment and activation of initiat ing caspases, release of IL 1R and IL18 citokines, inflam mation and inflammatory cell death. Although many MGCs refer to nucleic acid binding proteins or RNA DNA binding helicases, further study is necessary to assign them an antiviral function typical of intracellular NOD like and RIG like helicase receptors or some membrane bound TLRs.

With the possible excep tion of MGC02873, a Piwi like singleton suggestive of silencing and regulative events in germ cells and hema topoietic stem cells, and putative RNA helicases of the DEAD box family, we could not identify in Mytibase the core siRNA machinary Dcr 2, r2d2, AGO2 responsible for antiviral responses in Drosophila. Keeping in mind the 222 and 72 TLR gene models identified in the genome of Strongylocentrotus purpura tus and Branchiostoma floridae, respectively, the occasional presence in Mytibase of TLR related sequences is disappointing. In fact, only MGC03952, MGC06978, MGC07535 and few other LRR containing sequences display fragmentary similarity to human, fish and invertebrate TLR proteins. In the human TLRs, extracellular LRRs are arranged to recognize specific PAMPs whereas the intracellular Toll Interleukin 1 receptor domain activates down stream signalling pathways.

According to a recent com parative overview, Brefeldin_A the identification of authentic invertebrate TLRs cannot rely on the sequence homol ogy and requires functional studies. Present in Mytibase are also putative Ig like and MHC related surface antigens, sequences with a thyroglobulin domain typical of Insulin like Growth factor bind ing proteins and HLA class II invariant chain, and G Protein Coupled Receptors involved in the transduction of various signals and accounting for about 3% of human genes.