Myristoylation of Human Immunodeficiency Virus Type 1 gag Protein Is Required for Efficient env Protein Transportation to the Surface of Cells

Abstract

Highly conserved amino acids in the N-terminal region of the human immunodeficiency virus type 1 (HIV-1) Pr55gag are recognized to be critical for the attachment of myristic acid. We previously reported that the env protein was not detected on the cell surface by blocking of N-myristoylation of Pr55gag with N-myristoyl glycinal diethylacetal. Here, we constructed a mutant by substituting the N-terminal glycine of Pr55gag with alanine to demonstrate that N-myristoylation of Pr55gag is required for efficient env protein transportation to the cell surface. The expression level of the env protein on the surface of Jurkat cells transfected with the myristoylation-defective phenotype was observed to be significantly reduced by electron microscopic analyses with a gold-labeled monoclonal antibody against the env protein. In addition, Jurkat cells transfected with the myristoylation-defective phenotype lost the ability of envelope-mediated cell-to-cell fusion. The results suggest that N-myristoylation of the HIV-1 gag protein is necessary for efficient env protein transportation to the cell surface.