title: Opinion: Cell entry machines: a common theme in nature?
abstract: Molecular machines orchestrate the translocation and entry of pathogens through host cell membranes, in addition to the uptake and release of molecules during endocytosis and exocytosis. Viral cell entry requires a family of glycoproteins, and the structural organization and function of these viral glycoproteins are similar to the SNARE proteins, which are known to be involved in intracellular vesicle fusion, endocytosis and exocytosis. Here, we propose that a family of bacterial membrane proteins that are responsible for cell-mediated adherence and entry resembles the structural architecture of both viral fusion proteins and eukaryotic SNAREs and might therefore share similar, but distinct, mechanisms of cell membrane translocation. Furthermore, we propose that the recurrence of these molecular machines across species indicates that these architectural motifs were evolutionarily selected because they provided the best solution to ensure the survival of pathogens within a particular environment.
authors.affiliation: Department of Bioinformatics and Cellular Microbiology, Chiron Vaccines, Via Fiorentina 1, 53100 Siena, Italy.
authors.forename: Michèle A
authors.initials: MA
authors.lastname: Barocchi
authors.forename: Vega
authors.initials: V
authors.lastname: Masignani
authors.forename: Rino
authors.initials: R
authors.lastname: Rappuoli
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D000818:Animals; D001419:Bacteria / Q000472:pathogenicity*; D001424:Bacterial Infections / Q000382:microbiology; D004705:Endocytosis; D006801:Humans; D008561:Membrane Fusion; D008954:Models, Biological; D050600:SNARE Proteins; D015398:Signal Transduction; D033921:Vesicular Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D014760:Viral Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D014777:Virus Diseases / Q000382:microbiology; D018406:Virus Physiological Phenomena; D014780:Viruses / Q000472:pathogenicity
chemical_list: D018829:Adhesins, Bacterial; D050600:SNARE Proteins; D033921:Vesicular Transport Proteins; D014760:Viral Fusion Proteins