Receptor interacting protein 1 (RIP1) plays important roles not only in cell-death pathways but also in host innate immune responses. In the present study, a RIP1 ortholog named Lc-RIP1 was cloned and characterized in large yellow croaker (Larimichthys crocea). The open reading frame (ORF) of Lc-RIP1 is 2,046 bp, encoding a protein of 681 amino acids (aa), with an N-terminal kinase domain, an RHIM domain, and a C-terminal death domain. Subcellular localization analysis revealed that Lc -RIP1 was a cytosolic protein, which was broadly expressed in examined tissues/organs, and could be up-regulated under poly I:C, LPS, PGN, and Pseudomonas plecoglossicida stimulation in vivo based on qRT-PCR analysis. Notably, Lc -RIP1 could induce NF-κB, but not IRF3, IRF7 or type I IFN promoter activation. In addition, Lc -RIP1 overexpression could enhance Lc -MAVS, Lc -TRAF3, and Lc -TRAF6 mediated NF-κB promoter activation, and also Lc -TRIF and Lc -MAVS mediated IRF3 promoter activation, whereas suppress Lc -TRIF mediated NF-κB and type I IFN promoter activation, as well as Lc -TRAF3 and Lc -IRF3 mediated IRF3 promoter activation, Lc -IRF3 mediated type I IFN promoter activation and Lc -IRF7 mediated IRF7 promoter activation. These results collectively indicated that Lc -RIP1 function importantly in regulation of host innate immune signaling. • Lc-RIP1 can be induced by both viral and bacterial PAMPs stimulation. • Lc -RIP1 induces NF-κB, but not IRF3, IRF7 or type I IFN promoter activation. • Lc -RIP1 enhances MAVS, TRAF3, and TRAF6 mediated NF-κB activation, and also TRIF and MAVS mediated IRF3 activation. • Lc -RIP1 suppresses TRIF mediated NF-κB activation, and also TRAF3 and IRF3 mediated IRF3 activation. [ABSTRACT FROM AUTHOR]