title: MARCKS as a negative regulator of lipopolysaccharide signaling.
abstract: Myristoylated alanine-rich C kinase substrate (MARCKS) is an intrinsically unfolded protein with a conserved cationic effector domain, which mediates the cross-talk between several signal transduction pathways. Transcription of MARCKS is increased by stimulation with bacterial LPS. We determined that MARCKS and MARCKS-related protein specifically bind to LPS and that the addition of the MARCKS effector peptide inhibited LPS-induced production of TNF-α in mononuclear cells. The LPS binding site within the effector domain of MARCKS was narrowed down to a heptapeptide that binds to LPS in an extended conformation as determined by nuclear magnetic resonance spectroscopy. After LPS stimulation, MARCKS moved from the plasma membrane to FYVE-positive endosomes, where it colocalized with LPS. MARCKS-deficient mouse embryonic fibroblasts (MEFs) responded to LPS with increased IL-6 production compared with the matched wild-type MEFs. Similarly, small interfering RNA knockdown of MARCKS also increased LPS signaling, whereas overexpression of MARCKS inhibited LPS signaling. TLR4 signaling was enhanced by the ablation of MARCKS, which had no effect on stimulation by TLR2, TLR3, and TLR5 agonists. These findings demonstrate that MARCKS contributes to the negative regulation of the cellular response to LPS.
authors.affiliation: Department of Biotechnology, National Institute of Chemistry, Ljubljana 1000, Slovenia.
authors.forename: Mateja
authors.initials: M
authors.lastname: Mancek-Keber
authors.forename: Mojca
authors.initials: M
authors.lastname: Bencina
authors.forename: Bostjan
authors.initials: B
authors.lastname: Japelj
authors.forename: Gabriela
authors.initials: G
authors.lastname: Panter
authors.forename: Jörg
authors.initials: J
authors.lastname: Andrä
authors.forename: Klaus
authors.initials: K
authors.lastname: Brandenburg
authors.forename: Martha
authors.initials: M
authors.lastname: Triantafilou
authors.forename: Kathy
authors.initials: K
authors.lastname: Triantafilou
authors.forename: Roman
authors.initials: R
authors.lastname: Jerala
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D011992:Endosomes / Q000276:immunology; D005347:Fibroblasts / Q000276:immunology; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D007113:Immunity, Innate; D015850:Interleukin-6 / Q000096:biosynthesis / Q000276:immunology; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D008565:Membrane Proteins / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology; D011485:Protein Binding; D021381:Protein Transport / Q000276:immunology; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction; D051193:Toll-Like Receptors / Q000235:genetics / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000276:immunology
chemical_list: D015850:Interleukin-6; D047908:Intracellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides; C000619710:MARCKS protein, human; C000619711:Marcks protein, mouse; D008565:Membrane Proteins; D010455:Peptides; D034741:RNA, Small Interfering; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha; D000076250:Myristoylated Alanine-Rich C Kinase Substrate