Figure 1

Domain architectures of the MAGUK subfamilies and their distribution over the eukaryotic phyla. (A) Eight subfamilies have been identified as members of the MAGUK family in our study. Depicted here in a general schematic representation are the domains present in these members. All members contain a central core comprised of a GK domain and several N and/or C-terminally positioned PDZ domains. All members except the MAGI proteins contain a SH3 domain that is nested between a PDZ and the GK domain. The CASK and MPP proteins contain N-terminal L27 domains, while CARMA genes encode CARD domains at this position. Names used are allowing a more systematic, but do not reflect in all cases the commonly used names e.g. DLG4 is better known as PSD95. A list of synonyms is given in table 1. The CACNB subfamily, commonly not regarded as a canonical MAGUK subfamily, only contains the SH3 and GK domains. Phylogenetic analysis presented here however shows that it is a related subfamily. (B) The MAGUK subfamily distribution over the eukaryotic phyla shows no homologs were found for Choanozoans/Protozoans, Plantae and Fungi, here represented by Monosiga ovata, Arabidopsis thaliana and Saccharomyces cerevisae, respectively. Tetraodon nigroviridis has duplicated DLG4, ZO1 and ZO2 encoding genes, whereas Gallus gallus lacked the gene for DLG4. The arrowheads on the bottom indicate two possible gene duplication events.