Peroxinectin, a cell adhesive protein associated with the proPO system from the black tiger shrimp, Penaeus monodon.
Upon activation of the prophenoloxidase activating system in the shrimp, Penaeus monodon, a cell adhesion activity in the haemolymph is generated. A cell adhesion assay showed that a high number of granular cells (60%) adhered to coverslips coated with a shrimp haemocyte lysate supernatant, whereas a very low number of cells adhered to coverslips coated with bovine serum albumin. Inhibition of adhesion by an antiserum against crayfish peroxinectin, a cell adhesion protein, revealed that the cell adhesion activity detected in shrimp haemocyte lysate supernatant might result from a peroxinectin-like molecule in shrimp. A cDNA clone encoding shrimp peroxinectin was isolated, which had an open reading frame of 2337 nucleotides, with a polyadenylation sequence and a poly A tail. It encodes a protein of 778 amino acids including a 20 amino acid signal peptide. The mature protein (758 amino acids) has a predicted molecular mass of 84.8kDa and an estimated pI of 9.0. Two putative integrin binding motifs, RGD (Arg-Gly-Asp) and KGD (Lys-Gly-Asp), were found in shrimp peroxinectin. Sequence comparison shows that the shrimp protein is similar to crayfish peroxinectin (69%) and to various peroxidases and putative peroxidases from invertebrates and vertebrates. The shrimp peroxinectin cDNA also shows similarity (51%) to both Drosophila peroxinectin-related protein (AAF78217) and peroxidasin (S46224), an extracellular matrix protein combining an active peroxidase domain as well as immunoglobulin domains, leucine rich repeats and procollagen-like motif. However, the sequence similarity to both Drosophila molecules are mostly within the peroxidase domain. Northern blot analysis, using a non-peroxidase region in peroxinectin as a probe, revealed that peroxinectin is constitutively expressed in shrimp haemocyte and was reduced significantly in shrimp injected with a beta-1,3-glucan, laminarin, to mimic an infection with a fungus.
Sritunyalucksana
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Department of Comparative Physiology, Evolutionary Biology Center, Uppsala University, Norbyvägen 18A, SE-75236, Uppsala, Sweden.
Wongsuebsantati
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Johansson
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Söderhäll
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001798:Blood Proteins / Q000235:genetics / Q000378:metabolism*; D015152:Blotting, Northern; D004156:Catechol Oxidase / Q000378:metabolism*; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D018076:DNA, Complementary; D004792:Enzyme Precursors / Q000378:metabolism*; D008969:Molecular Sequence Data; D033561:Penaeidae; D017386:Sequence Homology, Amino Acid
D001798:Blood Proteins; D015815:Cell Adhesion Molecules; D018076:DNA, Complementary; D004792:Enzyme Precursors; C096867:peroxinectin protein, Pacifastacus leniusculus; C038451:pro-phenoloxidase; D004156:Catechol Oxidase