title: SecA-mediated targeting and translocation of secretory proteins.
abstract: More than 30 years of research have revealed that the dynamic nanomotor SecA is a central player in bacterial protein secretion. SecA associates with the SecYEG channel and transports polypeptides post-translationally to the trans side of the cytoplasmic membrane. It comprises a helicase-like ATPase core coupled to two domains that provide specificity for preprotein translocation. Apart from SecYEG, SecA associates with multiple ligands like ribosomes, nucleotides, lipids, chaperones and preproteins. It exerts its essential contribution in two phases. First, SecA, alone or in concert with chaperones, helps mediate the targeting of the secretory proteins from the ribosome to the membrane. Next, at the membrane it converts chemical energy to mechanical work and translocates preproteins through the SecYEG channel. SecA is a highly dynamic enzyme, it exploits disorder-order kinetics, swiveling and dissociation of domains and dimer to monomer transformations that are tightly coupled with its catalytic function. Preprotein signal sequences and mature domains exploit these dynamics to manipulate the nanomotor and thus achieve their export at the expense of metabolic energy. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
authors.affiliation: Institute of Molecular Biology and Biotechnology, FORTH, University of Crete, PO Box 1385, GR-711 10 Iraklio, Crete, Greece; KU Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, 3000 Leuven, Belgium.
authors.forename: Katerina E
authors.initials: KE
authors.lastname: Chatzi
authors.affiliation: KU Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, 3000 Leuven, Belgium.
authors.forename: Marios Frantzeskos
authors.initials: MF
authors.lastname: Sardis
authors.affiliation: Institute of Molecular Biology and Biotechnology, FORTH, University of Crete, PO Box 1385, GR-711 10 Iraklio, Crete, Greece; Department of Biology, University of Crete, PO Box 1385, GR-711 10 Iraklio, Crete, Greece; KU Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, 3000 Leuven, Belgium. Electronic address: tassos.economou@rega.kuleuven.be.
authors.forename: Anastassios
authors.initials: A
authors.lastname: Economou
authors.affiliation: Institute of Molecular Biology and Biotechnology, FORTH, University of Crete, PO Box 1385, GR-711 10 Iraklio, Crete, Greece; KU Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, 3000 Leuven, Belgium. Electronic address: lily.karamanou@rega.kuleuven.be.
authors.forename: Spyridoula
authors.initials: S
authors.lastname: Karamanou
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D020409:Molecular Motor Proteins / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport / Q000235:genetics*; D000069816:SEC Translocation Channels; D000081416:SecA Proteins
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D020409:Molecular Motor Proteins; D000069816:SEC Translocation Channels; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins
keywords: ATPase; Motor protein; Preproteins; Protein translocase; SecA; SecYEG