NMR structure of the myristylated feline immunodeficiency virus matrix protein.
Membrane targeting by the Gag proteins of the human immunodeficiency viruses (HIV types-1 and -2) is mediated by Gag's N-terminally myristylated matrix (MA) domain and is dependent on cellular phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2]. To determine if other lentiviruses employ a similar membrane targeting mechanism, we initiated studies of the feline immunodeficiency virus (FIV), a widespread feline pathogen with potential utility for development of human therapeutics. Bacterial co-translational myristylation was facilitated by mutation of two amino acids near the amino-terminus of the protein (Q5A/G6S; myrMAQ5A/G6S). These substitutions did not affect virus assembly or release from transfected cells. NMR studies revealed that the myristyl group is buried within a hydrophobic pocket in a manner that is structurally similar to that observed for the myristylated HIV-1 protein. Comparisons with a recent crystal structure of the unmyristylated FIV protein [myr(-)MA] indicate that only small changes in helix orientation are required to accommodate the sequestered myr group. Depletion of PI(4,5)P2 from the plasma membrane of FIV-infected CRFK cells inhibited production of FIV particles, indicating that, like HIV, FIV hijacks the PI(4,5)P2 cellular signaling system to direct intracellular Gag trafficking during virus assembly.
Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA. lola.brown@yale.edu.
Lola A
LA
Brown
Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA. cassiah.cox@nih.gov.
Cassiah
C
Cox
Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA. janaeb@umbc.edu.
Janae
J
Baptiste
Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA. hsummers@umbc.edu.
Holly
H
Summers
Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA. ryan.button@umaryland.edu.
Ryan
R
Button
Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA. kennedy.bahlow@temple.edu.
Kennedy
K
Bahlow
Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA. vspurrier@uchicago.edu.
Vaughn
V
Spurrier
Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA. jmk216@lehigh.edu.
Jenna
J
Kyser
Virus-Cell Interaction Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, Frederick, MD 21702-1201, USA. bxl244@case.edu.
Benjamin G
BG
Luttge
Virus-Cell Interaction Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, Frederick, MD 21702-1201, USA. kuols@mail.nih.gov.
Lillian
L
Kuo
Virus-Cell Interaction Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, Frederick, MD 21702-1201, USA. efreed@mail.nih.gov.
Eric O
EO
Freed
Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA. summers@hhmi.umbc.edu.
Michael F
MF
Summers
D000818:Animals; D002415:Cats; D002460:Cell Line; D016089:Immunodeficiency Virus, Feline / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D046188:Protein Modification, Translational; D021381:Protein Transport; D014763:Viral Matrix Proteins / Q000737:chemistry* / Q000378:metabolism
D019269:Phosphatidylinositol 4,5-Diphosphate; D014763:Viral Matrix Proteins