title: Modulation of membrane phosphoinositide dynamics by the phosphatidylinositide 4-kinase activity of the Legionella LepB effector.
abstract: Legionella pneumophila, the causative bacterium for Legionnaires' disease, hijacks host membrane trafficking for the maturation of the Legionella-containing vacuole (LCV). The LCV membrane mainly contains PtdIns4P, which is important for anchoring many secreted Legionella effectors onto the LCV. Here, we identify a cryptic functional domain (LepB_NTD) preceding the well-characterized RabGAP domain in the Legionella Dot/Icm type IV secretion system effector LepB. LepB_NTD alone is toxic to yeast and can disrupt the Golgi in mammalian cells. The crystal structure reveals an unexpected kinase fold and catalytic motif important for LepB_NTD function in eukaryotes. Cell biology-guided biochemical analyses uncovered a lipid kinase activity in LepB_NTD that specifically converts PtdIns3P into PtdIns(3,4)P2. PtdIns(3,4)P2is efficiently hydrolysed into PtdIns4P by another Dot/Icm effector SidF that is known to possess phosphoinositide phosphatase activity. Consistently, SidF is capable of counteracting the cellular functions of LepB_NTD. Genetic analyses show a requirement for LepB kinase activity as well as lipid phosphatase activity of SidF for PtdIns4P biosynthesis on the LCV membrane. Our study identifies an unprecedented phosphatidylinositide 4-kinase activity from bacteria and highlights a sophisticated manipulation of host phosphoinositide metabolism by a bacterial pathogen.
authors.affiliation: National Institute of Biological Sciences, Beijing 102206, China.
authors.forename: Na
authors.initials: N
authors.lastname: Dong
authors.affiliation: National Institute of Biological Sciences, Beijing 102206, China.|Graduate Program in Chinese Academy of Medical Sciences and Beijing Union Medical College, Beijing 100730, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Niu
authors.affiliation: National Institute of Biological Sciences, Beijing 102206, China.
authors.forename: Liyan
authors.initials: L
authors.lastname: Hu
authors.affiliation: National Institute of Biological Sciences, Beijing 102206, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Yao
authors.affiliation: National Institute of Biological Sciences, Beijing 102206, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhou
authors.affiliation: National Institute of Biological Sciences, Beijing 102206, China.|National Institute of Biological Sciences, Collaborative Innovation Center for Cancer Medicine, Beijing 102206, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Shao
mesh_terms: D019870:1-Phosphatidylinositol 4-Kinase / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D018360:Crystallography, X-Ray; D054884:Host-Pathogen Interactions; D016952:Legionella pneumophila / Q000378:metabolism*; D010711:Phosphatidate Phosphatase; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism*; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; C482639:LepB protein, Legionella pneumophila; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; C060980:phosphatidylinositol 3,4-diphosphate; C055525:phosphatidylinositol 3-phosphate; C037178:phosphatidylinositol 4-phosphate; D019870:1-Phosphatidylinositol 4-Kinase; C112948:lipid phosphate phosphatase; D010711:Phosphatidate Phosphatase