Scavenger receptor class B type I (SR-BI) in Ruditapes philippinarum: A versatile receptor with multiple functions.
In the present study, a scavenger receptor class B type I (designed as RpSR-BI) was cloned and characterized from manila clam Ruditapes philippinarum. The full-length cDNA of RpSR-BI was of 2000 bp, containing an open reading frame (ORF) of 1515 bp. Multiple alignments and phylogenetic analysis strongly suggested that RpSR-BI was a member of the scavenger receptors family. The mRNA transcript of RpSR-BI was constitutively expressed in all tested tissues, and mainly expressed in hepatopancreas and hemocytes. Generally, Vibrio anguillarum or Micrococcus luteus challenge induced the expression of RpSR-BI transcripts in hemocytes of manila clams. Recombinant protein of RpSR-BI (rRpSR-BI) could bind lipopolysaccharides, peptidoglycan and glucan, but not chitin in vitro. Coinciding with the PAMPs binding assay, a broad agglutination spectrum was displayed by rRpSR-BI including Gram-positive bacteria and Gram-negative bacteria. Moreover, rRpSR-BI could enhance the phagocytosis and chemotaxis of hemocytes. These results showed that RpSR-BI functioned as a pattern recognition receptor (PRR) with distinct recognition spectrum, and also as an opsonin involved in the innate immune response of R. philippinarum.
['Yang|Dinglong|D|', 'Han|Yijing|Y|', 'Chen|Lizhu|L|', 'Liu|Yongliang|Y|', 'Cao|Ruiwen|R|', 'Wang|Qing|Q|', 'Zhao|Jianmin|J|']
D000372:Agglutination Tests D000818:Animals D049872:Bivalvia D006090:Gram-Negative Bacteria D006094:Gram-Positive Bacteria D006434:Hemocytes D043143:Hepatopancreas D007113:Immunity, Innate D000069452:Pathogen-Associated Molecular Pattern Molecules D010802:Phylogeny D051192:Receptors, Pattern Recognition D051116:Receptors, Scavenger
Scavenger receptor Ruditapes philippinarum Pattern recognition receptor Immune recognition