title: Membrane fusion during phage lysis.
abstract: In general, phages cause lysis of the bacterial host to effect release of the progeny virions. Until recently, it was thought that degradation of the peptidoglycan (PG) was necessary and sufficient for osmotic bursting of the cell. Recently, we have shown that in Gram-negative hosts, phage lysis also requires the disruption of the outer membrane (OM). This is accomplished by spanins, which are phage-encoded proteins that connect the cytoplasmic membrane (inner membrane, IM) and the OM. The mechanism by which the spanins destroy the OM is unknown. Here we show that the spanins of the paradigm coliphage lambda mediate efficient membrane fusion. This supports the notion that the last step of lysis is the fusion of the IM and OM. Moreover, data are provided indicating that spanin-mediated fusion is regulated by the meshwork of the PG, thus coupling fusion to murein degradation by the phage endolysin. Because endolysin function requires the formation of μm-scale holes by the phage holin, the lysis pathway is seen to require dramatic dynamics on the part of the OM and IM, as well as destruction of the PG.
authors: Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128; and.
authors: Manoj
authors: http://orcid.org/0000-0002-0440-6222
authors: M
authors: Rajaure
authors: Department of Microbiology, Pasteur Institute, 75724 Paris, France.
authors: Joel
authors: J
authors: Berry
authors: Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128; and.
authors: Rohit
authors: R
authors: Kongari
authors: Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128; and.
authors: Jesse
authors: J
authors: Cahill
authors: Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128; and ryland@tamu.edu.
authors: Ry
authors: R
authors: Young
mesh_terms: D010582:Bacteriophage lambda / Q000502:physiology*; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D010450:Endopeptidases / Q000235:genetics / Q000502:physiology*; D004926:Escherichia coli / Q000235:genetics / Q000821:virology*; D008561:Membrane Fusion; D010457:Peptidoglycan / Q000235:genetics / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D057074:Virus Release / Q000502:physiology*
chemical_list: D010457:Peptidoglycan; D014764:Viral Proteins; D010450:Endopeptidases; C001143:endolysin
keywords: endolysin; holin; membrane fusion; spanin; spheroplast