title: Identification and activity of a paralog of cathepsin S from yellow catfish (Pelteobagrus fulvidraco) involved in immune response.
abstract: Cathepsin S, a papain-like cysteine peptidase, is an important regulator and signaling molecule with diverse biological actions in addition to immune presentation. However, our understanding of its structure and properties remains limited. Herein, a full-length cathepsin Sa from yellow catfish was cloned and named PfCTSSa. It contained 1366 bp, including a 981 bp ORF flanked by a 123 bp 5'-untranslated region (UTR) and a 262 bp 3'-UTR. This ORF encoded a 36.5 kD cysteine protease with the deduced amino acid sequence having a 76% sequence identity with Ictalurus punctatus ctssa. Additionally, PfCTSSa was found to be a paralog of cathepsin S since it generated a new cluster with cathepsin Sa in the phylogenic tree. Furthermore, PfCTSSa was found to contain more N-glycosylation sites than cathepsin S. The recombinant PfCTSSa was overexpressed in E. coli BL21 (DE3) and appeared to have the strongest activity at pH 8.5 and 35 °C in a concentration-dependent manner, with activity further affected by metal ions and detergents. Moreover, PfCTSSa mRNA was highly expressed in classic and mucosal immune tissues, although constitutively distributed in all of the examined tissues. Yellow catfish were then challenged with inactivated Aeromonas hydrophila and PfCTSSa was remarkably increased in the head kidney, liver and spleen when compared to the PBS control. Collectively, these results indicate that PfCTSSa is a paralog of cathepsin S and functions in the yellow catfish immune response.
authors.affiliation: College of Life Sciences and Engineering, Henan University of Urban Construction, Pingdingshan 467036, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Life Sciences and Engineering, Henan University of Urban Construction, Pingdingshan 467036, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Life Sciences and Engineering, Henan University of Urban Construction, Pingdingshan 467036, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Lv
authors.affiliation: College of Life Sciences and Engineering, Henan University of Urban Construction, Pingdingshan 467036, China.
authors.forename: Jinnan
authors.initials: J
authors.lastname: Ren
authors.affiliation: College of Life Sciences and Engineering, Henan University of Urban Construction, Pingdingshan 467036, China. Electronic address: kefei027@qq.com.
authors.forename: Fei
authors.initials: F
authors.lastname: Ke
mesh_terms: D016980:Aeromonas hydrophila / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002397:Catfishes / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D002403:Cathepsins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007113:Immunity, Innate; D009928:Organ Specificity; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D002403:Cathepsins; C028217:cathepsin S
keywords: Aeromonas hydrophila; Cathepsin Sa; Enzyme assay; Immune response; Yellow catfish