HP0135 Is a Small Lipoprotein That Has a Role in Outer Membrane Stability.

is a Gram-negative bacterium and human pathogen that is linked to various gastric diseases, including peptic ulcer disease, chronic gastritis, and gastric cancer. The filament of the flagellum is surrounded by a membranous sheath that is contiguous with the outer membrane. Proteomic analysis of isolated sheathed flagella from B128 identified the lipoprotein HP0135 as a potential component of the flagellar sheath. HP0135 is a small protein, with the mature HP0135 lipoprotein only 28 amino acid residues in length. Deletion of in B128 resulted in morphological abnormalities that included extensive formation of outer membrane vesicles and increased frequency of mini-cells. Introducing a plasmid-borne copy of into the Δ mutant suppressed the morphological abnormalities. The phenotype of the Δ mutant suggests HP0135 has roles in stabilizing the cell envelope and cell division.