Identification of cathepsin B from large yellow croaker (Pseudosciaena crocea) and its role in the processing of MHC class II-associated invariant chain.
In teleost, cathepsin B has been identified from several species and shown to play roles in the host immune response during pathogen challenge. However, the mechanism of how cathepsin B modulates the immune response in teleosts remains poorly understood. In this study, we identified and characterized cathepsin B (LycCatB) and invariant chain (LycIi) from the large yellow croaker (Pseudosciaena crocea). Sequence comparison and phylogenetic analysis indicated that LycCatB and LycIi are highly conserved within teleosts. Quantitative RT-PCR analysis showed that LycCatB mRNA was widely expressed in all examined tissues. We then recombinantly expressed LycCatB and Lyc-TR-Ii (transmembrane domain removed Ii chain) in Pichia pastoris and Escherichiacoli, respectively. The recombinant LycCatB (rLycCatB) can hydrolyze the substrate Z-FR-AMC with a Km value of 40.68μM. Furthermore, co-incubation of rLycCatB with rLyc-TR-Ii led to an efficient cleavage of rLyc-TR-Ii in a time-dependant manner. These results indicated that cathepsin B may be involved in MHC class II-associated Ii processing in large yellow croaker, and provide new information helping to elucidate the immunological functions of teleost cathepsin B.
Key Laboratory of Marine Biogenetics and Resources, Third Institute of Oceanography, State Oceanic Administration, 184 Daxue Road, Xiamen 361005, China.
Mingyu
M
Li
Key Laboratory of Marine Biogenetics and Resources, Third Institute of Oceanography, State Oceanic Administration, 184 Daxue Road, Xiamen 361005, China.
Qiuhua
Q
Li
Key Laboratory of Marine Biogenetics and Resources, Third Institute of Oceanography, State Oceanic Administration, 184 Daxue Road, Xiamen 361005, China.
Zhijun
Z
Yang
Key Laboratory of Marine Biogenetics and Resources, Third Institute of Oceanography, State Oceanic Administration, 184 Daxue Road, Xiamen 361005, China.
Guohai
G
Hu
Key Laboratory of Marine Biogenetics and Resources, Third Institute of Oceanography, State Oceanic Administration, 184 Daxue Road, Xiamen 361005, China.
Ting
T
Li
Key Laboratory of Marine Biogenetics and Resources, Third Institute of Oceanography, State Oceanic Administration, 184 Daxue Road, Xiamen 361005, China. Electronic address: Chenxinhua@tio.org.cn.
Xinhua
X
Chen
Key Laboratory of Marine Biogenetics and Resources, Third Institute of Oceanography, State Oceanic Administration, 184 Daxue Road, Xiamen 361005, China. Electronic address: ajingqun@tio.org.cn.
Jingqun
J
Ao
D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation; D000944:Antigens, Differentiation, B-Lymphocyte / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D002401:Cathepsin B / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D029941:Fish Proteins / Q000235:genetics* / Q000276:immunology*; D005802:Genes, MHC Class II; D000949:Histocompatibility Antigens Class II / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D008969:Molecular Sequence Data; D010473:Perciformes / Q000235:genetics* / Q000276:immunology; D010802:Phylogeny; D011994:Recombinant Proteins / Q000235:genetics
D000944:Antigens, Differentiation, B-Lymphocyte; D029941:Fish Proteins; D000949:Histocompatibility Antigens Class II; D011994:Recombinant Proteins; C045084:invariant chain; D002401:Cathepsin B
Antigen presentation; Cathepsin B; Invariant chain processing; Large yellow croaker