HIV-1 Nef membrane association depends on charge, curvature, composition and sequence.
Nef-mediated internalization of T-cell receptor molecules from the surface of an infected cell is required for the pathogenicity of HIV and disease progression to AIDS. This function depends on the N-terminal myristoylation of Nef, a lipid modification that targets the protein to membranes. We have analyzed how specific membrane properties and sequence motifs within Nef determine this interaction. Using time-resolved techniques we find that the association with membranes is a biphasic process with a fast rate for an electrostatic-driven protein-liposome interaction and a slow rate for the formation of an amphipathic helix. The rate of myristate insertion into liposomes depends on membrane curvature, while changes in the lipid composition with respect to phosphoinositides, cholesterol or sphingomyelin did not significantly alter the interaction. Moreover, Nef binding to membranes requires negatively charged liposomes, and mutations of basic and hydrophobic residues strongly diminished the association and changed the binding kinetics differently.
Gerlach
Holger
H
Max-Planck-Institut für molekulare Physiologie, Abteilung Physikalische Biochemie, Dortmund, Germany.
Laumann
Vanessa
V
Martens
Sascha
S
Becker
Christian F W
CF
Goody
Roger S
RS
Geyer
Matthias
M
D020816:Amino Acid Motifs; D000818:Animals; D019556:COS Cells; D002462:Cell Membrane / Q000821:virology*; D002522:Chlorocebus aethiops; D002784:Cholesterol / Q000737:chemistry; D015658:HIV Infections / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008055:Lipids / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry; D009227:Myristic Acids / Q000737:chemistry; D017433:Protein Structure, Secondary; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D013109:Sphingomyelins / Q000737:chemistry; D054311:nef Gene Products, Human Immunodeficiency Virus / Q000378:metabolism*
D008055:Lipids; D008081:Liposomes; D009227:Myristic Acids; D011948:Receptors, Antigen, T-Cell; D013109:Sphingomyelins; D054311:nef Gene Products, Human Immunodeficiency Virus; D002784:Cholesterol