PT - JOURNAL ARTICLE AU - Jens Staal AU - Yasmine Driege AU - Paco Hulpiau AU - Rudi Beyaert TI - The Bcl10/paracaspase signalling complex is functionally conserved since the last common ancestor of planulozoa AID - 10.1101/046789 DP - 2016 Jan 01 TA - bioRxiv PG - 046789 4099 - http://biorxiv.org/content/early/2016/04/02/046789.short 4100 - http://biorxiv.org/content/early/2016/04/02/046789.full AB - A single MALT1, cleavage and CLAP: an old story. The type 1 paracaspases are defined by their domain composition with an N-terminal Death-domain, immunoglobulin domains and a caspase-like (paracaspase) domain. Type 1 paracaspases originated in the edicarian geological period before the last common ancestor of bilaterans and cnidarians (planulozoa). Most organisms have a single type 1 paracaspase, except vertebrates where a triplication occurred in the ancestral jawed vertebrate. Mammals have lost two of the paralogs and only contain a single paracaspase (paracaspase-1, MALT1). Cnidarians have several paralog type 1 paracaspases, type 2 paracaspases, and a homolog of Bcl10 (CLAP). Notably in bilaterans, lineages like nematodes and insects lack Bcl10 whereas other lineages such as vertebrates, annelids, molluscs and acorn worms do contain Bcl10. There seems to be a correlation where invertebrates with Bcl10 have type 1 paracaspases which are more similar to the paracaspases found in vertebrates. A proposed evolutionary scenario includes two ancestral type 1 paracaspase paralogs in the bilateran last common ancestor, where one paralog usually is dependent on Bcl10 for its function. Functional analyses of invertebrate type 1 paracaspases and Bcl10 homologs support this scenario and indicate an ancient origin of the Bcl10/paracaspase signalling complex.