The truncated insulin receptor-like sequences in arthropods span the receptor L1 domain (green oval), the furin-like domain (orange) and the receptor L2 domain (green oval). In most cases, they also contain between 1 and 3 fibronectin domains (grey diamond) and a transmembrane domain (blue pentagon). The putative truncated splice variants of INSRR identified in human brain cDNA are much shorter, encompassing only the L1 domain (green oval), the furin-like domain (orange), and in the longer variant, half of the L2 domain (green oval). Created using http://prosite.expasy.org/cgi-bin/prosite/mydomains/.