Involvement of caveolin-1 in the Jak–Stat signaling pathway and infectious spleen and kidney necrosis virus infection in mandarin fish (Siniperca chuatsi)

Abstract

Caveolae, the major source of caveolin-1 protein, are specialized invaginated microdomains of the plasma membrane that act as organizing centers for signaling molecules in the immune system. In the present study, we report the cloning and characterization of caveolin-1 (mCav-1) from mandarin fish (Siniperca chuatsi) and study on the roles of mCav-1 in the fish Jak-Stat signaling pathway and in virus infection. The cDNA sequence of mCav-1 was 707bp in size, encoding a protein of 181 amino acids, which was different from the mammalian protein (178 amino acids). The deduced amino acid sequence of mCav-1 shared similar architecture with vertebrate caveolin-1 proteins, but mCav-1 lacked a phosphorylation site (y14). The major subcellular location of mCav-1 was in the caveolae, where the protein appeared to have major functions. Real-time PCR revealed that the expression of the mandarin fish Mx, IRF-1, SOCS1, and SOCS3 genes involved in the poly(I:C)-induced Jak-Stat signaling pathway was impaired by the mCav-1 scaffolding domain peptide (mSDP). In mandarin fish fry (MFF-1) cells, the protein levels of mCav-1 were markedly up-regulated at 12 and 24h post-infection with ISKNV (infectious spleen and kidney necrosis virus). In addition, ISKNV entry into MFF-1 cells was significantly inhibited by mSDP, and the inhibition was dose-dependent. Thus, ISKNV infection was apparently associated with mCav-1 protein and may utilize the caveolae-related endocytosis pathway. The findings reported here further our understanding of the function of caveolin-1 in the complex signal transduction network in fish immune systems and in the cellular entry mechanism of iridoviruses.

Cavin-1: caveolae-dependent signalling and cardiovascular disease

“…Interestingly, TLR3-dependent polyinosinic-polycytidylic acid-induced gene expression of SOCS3 is down-regulated in mandarin fish (Siniperca chuatsi) following expression of the scaffold domain of a caveolin-1 homologue [26]. As such, structural components of caveolae might be involved in the regulation of cytokine signalling at several levels.…”

Caveolin-1 Plays a Critical Role in the Differentiation of Monocytes into Macrophages

“…29,30 Because caveolin-1 has been demonstrated to regulate β1-integrin signaling, 31 we can speculate that caveolin-1 also modulates β2-integrins to influence differentiation. Also, as the transcription factor IRF-8/ICSBP has been identified as a regulator of macrophage maturation 32 and caveolin-1 has been reported to influence its activation through the Janus kinase/signal transducers and activators of transcription signal pathway, 33 this may be another means by which caveolin-1 influences differentiation.…”

Mandarin Fish Caveolin 1 Interaction with Major Capsid Protein of Infectious Spleen and Kidney Necrosis Virus and Its Role in Early Stages of Infection

“…MFF-1 cells were maintained in DMEM supplemented with 10% FBS and passaged every 3 to 4 days via trypsinization in monolayer cultures at 27°C under a humidified atmosphere of 5% CO 2 (27). Rabbit polyclonal anti-MCP, anti-ORF101L, and anti-mCav-1 and mouse polyclonal anti-mCav-1 antisera were previously generated in our laboratory (26). Mouse monoclonal antibodies (Abs) raised against ␣-actin, the Flag tag, the green fluorescent protein (GFP) tag, the glutathione S-transferase (GST) tag, the maltose-binding protein (MBP) tag, ␤-tubulin, and the V5 tag were obtained from Sigma-Aldrich (St. Louis, MO).…”

“…We previously reported that ISKNV may internalize into mandarin fish fry (MFF-1) cells through a caveola-dependent endocytic pathway (25,26). We postulated that certain ISKNV proteins may interact with mandarin fish Cav-1 (mCav-1).…”