title: Cloning and biochemical characterization of astacin-like squid metalloprotease.
abstract: We have cloned four cDNAs encoding astacin-like squid metalloproteases (ALSMs)-I and -II from the Japanese common squid and ALSMs-I and -III from the spear squid. Analysis of the deduced amino acid sequences revealed that ALSMs possess a signal peptide and a pro-sequence followed by an astacin-like catalytic domain and an MAM (meprin, A5 protein, receptor protein-tyrosine phosphatase mu) domain. Phylogenetic analysis revealed that ALSM corresponds to a new cluster of astacins. To analyze the function of the MAM domain, wild-type ALSM and an MAM-truncated mutant were expressed in a baculovirus expression system. The expressed protein encoding full-length ALSM hydrolyzed myosin heavy chain as effectively as native ALSM, whereas the MAM-truncated mutant possessed no protease activity, suggesting that the MAM domain contributes to substrate recognition. ALSM has been isolated from squid liver and mantle muscle. However, analysis with a specific antibody generated against ALSM indicated the presence of ALSM in a wide variety of tissues. ALSM was located in the extracellular matrix of mantle muscle cells. Thus, ALSM is a secreted protease, as are other members of the astacin family. The extracellular localization raises the possibility of substrates other than myosin. The physiological role of ALSM remains unknown, at this time.
authors.affiliation: Department of Chemistry, Faculty of Science and Technology, Sophia University, Tokyo 102-8554.
authors.forename: Yuya
authors.initials: Y
authors.lastname: Yokozawa
authors.forename: Hitomi
authors.initials: H
authors.lastname: Tamai
authors.forename: Shuntaro
authors.initials: S
authors.lastname: Tatewaki
authors.forename: Takaho
authors.initials: T
authors.lastname: Tajima
authors.forename: Takahide
authors.initials: T
authors.lastname: Tsuchiya
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kanzawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016367:Baculoviridae; D003001:Cloning, Molecular; D049832:Decapodiformes / Q000235:genetics* / Q000378:metabolism*; D005822:Genetic Vectors; D015151:Immunoblotting; D007150:Immunohistochemistry; D008666:Metalloendopeptidases / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009132:Muscles / Q000378:metabolism; D009928:Organ Specificity; D020033:Protein Isoforms; D017422:Sequence Analysis, DNA
chemical_list: D020033:Protein Isoforms; D008666:Metalloendopeptidases; C071288:astacin