IpaH7.8 intracellular location and secretion patterns.

Abstract

Shigella is an environmental contaminant of water and food in many countries throughout the world. To infect cells of the large intestine Shigella employs the use of the type III secretion system (TTSS). The TTSS is present in many animal and plant pathogens other than Shigella. Several effector proteins secreted by Shigella via the TTSS during invasion show significant homology between species. In this study the intracellular location of IpaH7.8 and its secretion pattern in several key mutants (SF619, SF620 and SF621) was evaluated. Secretion patterns from IpaB and IpaC mutants suggest that wild type secretion of IpaH7.8 is dependent upon their presence. To determine intracellular location, fusions of IpaH7.8, IpaH9.8, lpgB1, and IpaB to GFP in mammalian expression vectors were used to transfect HeLa cells. HeLa cells transfected with IpaH7.8-GFP and IpaH9.8-GFP showed significant concentration of the IpaH proteins in the nucleus of the cells. lpgB1-GFP was located exclusively in the mitochondria and IpaB was located in the cytoplasm. The findings of this research show that IpaH7.8, like its homologs YopM and IpaH9.8, is transported to the nucleus of HeLa cells.