title: Phylogenetic distribution of protease inhibitors of the Kazal-family within the Arthropoda.
abstract: In mammalian pancreatic cells, the pancreatic secretory trypsin inhibitor (PSTI) belonging to the Kazal-family prevents the premature activation of digestive enzymes and thus plays an important role in a protective mechanism against tissue destruction by autophagy. Although a similar protective mechanism exists in Arthropoda, the distribution of these inhibitors in this phylum remains obscure. A comprehensive in silico search of nucleotide databases, revealed the presence of members of the Kazal-family in the four major subphyla of the Arthropoda. Especially in the Hexapoda and the Crustacea these inhibitors are widespread, while in the Chelicerata and Myriapoda only a few Kazal-like protease inhibitors were found. A sequence alignment of inhibitors retrieved in the digestive system of insects revealed a conservation of the PSTI characteristics and strong resemblance to vertebrate PSTI. A phylogenetic analysis of these inhibitors showed that they generally cluster according to their order. The results of this data mining study provide new evidence for the existence of an ancient protective mechanism in metazoan digestive systems. Kazal-like inhibitors, which play an important protective role in the pancreas of vertebrates, also seem to be present in Arthropoda.
authors.affiliation: Department of Animal Physiology and Neurobiology, Zoological Institute KU Leuven, Leuven, Belgium. Vincent.vanHoef@bio.kuleuven.be
authors.forename: Vincent
authors.initials: V
authors.lastname: van Hoef
authors.forename: Bert
authors.initials: B
authors.lastname: Breugelmans
authors.forename: Jornt
authors.initials: J
authors.lastname: Spit
authors.forename: Gert
authors.initials: G
authors.lastname: Simonet
authors.forename: Sven
authors.initials: S
authors.lastname: Zels
authors.forename: Jozef
authors.initials: J
authors.lastname: Vanden Broeck
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001181:Arthropods / Q000235:genetics*; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D014359:Trypsin Inhibitor, Kazal Pancreatic / Q000737:chemistry / Q000235:genetics*
chemical_list: D019476:Insect Proteins; D014359:Trypsin Inhibitor, Kazal Pancreatic