title: Ability of the hydrophobic fusion-related external domain of a paramyxovirus F protein to act as a membrane anchor.
abstract: The hydrophobic NH2 terminus of F1 (FRED) of the simian virus 5 fusion (F) protein is implicated in mediating cell fusion, but in the inactive F0 precursor the FRED is translocated across membranes. Hybrid proteins containing the FRED as a potential membrane anchorage domain and a mutant of F0 lacking the preceding five-arginine cleavage/activation site were used to study the effect of position on the FRED. The experiments indicate that the SV5 F protein has evolved an exquisite control system for biological activity: the FRED is close to the threshold of hydrophobicity required to function as a membrane anchor. The FRED is not sufficiently hydrophobic to halt translocation when in an internal position, but on cleavage/activation the threshold of hydrophobicity is effectively lowered, and the FRED, now the NH2 terminus of F1, is able to interact stably with membranes.
mesh_terms: D000118:Acetylglucosaminidase / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism; D006389:Hemagglutinins, Viral; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D011498:Protein Precursors / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D018108:Respirovirus / Q000378:metabolism*; D013539:Simian virus 40; D014760:Viral Fusion Proteins / Q000378:metabolism*
chemical_list: D006389:Hemagglutinins, Viral; D011498:Protein Precursors; D011994:Recombinant Proteins; D014760:Viral Fusion Proteins; D000118:Acetylglucosaminidase; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase