tailieunhanh - Báo cáo khoa học: Proteolytic activation and function of the cytokine Spatzle in the innate immune response of a lepidopteran insect, Manduca sexta

The complexes formed by partially folded human and bovine a-lactalbumin with oleic acid (OA) have been reported to display selective apoptotic activity against tumor cells. These complexes were named human (HAMLET) or bovine (BAMLET) alpha-lactalbumin made lethal to tumor cells. | Proteolytic activation and function of the cytokine Spatzle in the innate immune response of a lepidopteran insect Manduca sexta Chunju An1 Haobo Jiang2 and Michael R. Kanost1 1 Department of Biochemistry Kansas State University Manhattan KS USA 2 Department of Entomology and Plant Pathology Oklahoma State University Stillwater OK USA Keywords antimicrobialpeptides innate immunity Manduca sexta proteolytic activation Spatzle Correspondence M. R. Kanost Department of Biochemistry 141 Chalmers Hall Kansas State University Manhattan KS 66506 USA Fax 1 785 532 7278 Tel 1 785 532 6964 E-mail kanost@ Database The DNA and protein sequenced have been submitted to the NCBI database under the accession numbers GQ249944 GQ249945 and GQ249956 Received 20 August 2009 revised 15 October 2009 accepted 27 October 2009 doi The innate immune response of insects includes induced expression of genes encoding a variety of antimicrobial peptides. The signaling pathways that stimulate this gene expression have been well characterized by genetic analysis in Drosophila melanogaster but are not well understood in most other insect species. One such pathway involves proteolytic activation of a cytokine called Spatzle which functions in dorsal-ventral patterning in early embryonic development and in the antimicrobial immune response in larvae and adults. We have investigated the function of Spatzle in a lepidopteran insect Manduca sexta in which hemolymph proteinases activated during immune responses have been characterized biochemically. Two cDNA isoforms for M. sexta Spiitzle-l differ because of alternative splicing resulting in a 10 amino acid residue insertion in the pro-region of proSpatzle-lB that is not present in proSpatzle-lA. The proSpatzle-lA cDNA encodes a kDa polypeptide that is 23 and 44 identical to D. melanogaster and Bombyx mori Spiitzle-l. respectively. Recombinant proSpiitzle-lA was a disulfide-linked homodimer. M. sexta .