고려대학교

초록/요약

Salmonella enterica serovar Typhimurium translocates effector proteins to host epithelial cell through the Type Three Secretion System (TTSS). Upon Salmonella entry into host cell, SipB encoded from Salmonella pathogenicity island 1 (SPI-1) is translocated via SPI-I TTSS. In this study, I made various recombinant constructs of SipB N-terminus. Western blotting experiment showed that N-terminus 160 amino acid of SipB is secreted into extracellular supernatant and its secretion was dependent upon flagellar TTSS, not upon SPI-1 TTSS. Using GST pull-down assay I found that SicA, chaperone of SipB, was able to bind SipB N-terminus, but is not involved in secretion of SipB. I fused C-terminus 93 amino acid residue of SipB which is predicted to possess the chaperone binding domain with SipB N-terminus 160. Secretion level of this plasmid on SPI-1 mutant is more than wild type. Therefore, I propose that secretion through SPI-1 TTSS of na？ve SipB might be mediated by the C-terminal region, not by N-terminal region.