title: Lipidation of the autotransporter NalP of Neisseria meningitidis is required for its function in the release of cell-surface-exposed proteins.
abstract: Autotransporters of Gram-negative bacteria consist of an N-terminal signal sequence, a C-terminal translocator domain and the secreted passenger domain in between. The autotransporter NalP of Neisseria meningitidis includes a protease domain that facilitates the release of several immunogenic proteins from the cell surface into the extracellular milieu. Rather exceptionally among autotransporters, NalP is a lipoprotein. We investigated the role of lipidation in the biogenesis and function of the protein. To this end, the N-terminal cysteine, which is lipidated in the wild-type protein, was substituted by alanine. Like the wild-type protein, the mutant protein was secreted into the medium, demonstrating that lipidation is not required for biogenesis of the protein. However, the non-lipidated NalP variant had a drastically reduced capacity to cleave its substrate proteins from the cell surface, suggesting that the lipid moiety is important for function. Kinetic experiments demonstrated that the autocatalytic processing of the non-lipidated protein at the cell surface was much faster than that of the wild-type protein. Thus, the lipid moiety delays the release of NalP from the cell surface, thereby allowing it to release other surface-exposed proteins into the milieu.
authors.affiliation: Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, The Netherlands.
authors.forename: Virginie
authors.initials: V
authors.lastname: Roussel-Jazédé
authors.affiliation: Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Grijpstra
authors.affiliation: Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, The Netherlands.
authors.forename: Vincent
authors.initials: V
authors.lastname: van Dam
authors.affiliation: Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Tommassen
authors.affiliation: Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, The Netherlands.
authors.forename: Peter
authors.initials: P
authors.lastname: van Ulsen
mesh_terms: D000409:Alanine / Q000235:genetics / Q000378:metabolism; D019943:Amino Acid Substitution; D003545:Cysteine / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D050356:Lipid Metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D009345:Neisseria meningitidis / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*
chemical_list: D026901:Membrane Transport Proteins; D050505:Mutant Proteins; C480853:NalP protein, Neisseria meningitidis; D012697:Serine Endopeptidases; D003545:Cysteine; D000409:Alanine