Variants of CCR5, which are permissive for HIV-1 infection, show distinct functional responses to CCL3, CCL4 and CCL5

Abstract

CCR5 is one of the primary coreceptors for Env-mediated fusion between cells and human immunodeficiency virus type 1 (HIV-1). Analyses of CCR5 variants in cohorts of HIV-1 high-risk individuals led to the identification of multiple single amino-acid substitutions, which may have functional consequences. This study focused on eight naturally occurring allelic variants located between amino-acid residues 60 and 334 of CCR5. All studied allelic variants were highly expressed on the cell surface of HEK-293 cells and permissive for HIV-1 infection. Variant G301V showed 3.5-fold increase in 50% effective concentration (EC 50 ) for CCL4 (MIP 1beta) in a competitive binding assay. There was also a significant reduction in CCL5 (RANTES) EC 50 for the R223Q, A335V and Y339F variants. The most unexpected functional abnormality was exhibited by the R60S variant that exhibited a loss of ligand-induced desensitization in chemotaxis assays, but showed normal CCL4 and CCL5 binding avidity. This mutation is located in the first intracellular loop, a domain that has not previously been shown to be involved in receptor desensitization. In conclusion, our results support earlier studies showing that these naturally occurring point mutations do not limit HIV-1 infection, and indicated that single amino-acid changes can have unexpected functional consequences.

mRNA transfection of a novel TAL effector nuclease (TALEN) facilitates efficient knockout of HIV co-receptor CCR5

“…To overcome this limitation we designed a novel, codon-optimized CCR5-specific TALEN (CCR5-Uco-TALEN) (Figure 1A ). Both TALEN arms recognize 19-bp target sequences within the CCR5 gene corresponding to the very short first intracellular loop of CCR5 (Figure 1B ), a region expected to be sensitive for amino-acid deletions or substitutions ( 30 , 31 ). A search for potential off-target sites using the Paired-Target Finder ( 19 ) identified the closest sequence (harboring six mismatches) within the CCR2 gene (Figure 1C ) and a second one in the MUC16 gene (10 mismatches) (see below).…”

Identification of the CCR5-Δ32 HIV resistance allele and new mutations of the CCR5 gene in different Tunisian populations

“…In fact, 20%, 38%, and 43% of the populations of Tunis, Sejnane, and Chenini-Douiret, respectively, carried at least one CCR5 mutation. Among these mutations, CCR5-⌬32 and L55Q-C101X, which produce a truncated protein, have been shown to affect CCR5 gene expression and function and are associated with resistance to HIV infection and disease progression [13,[23][24][25]34].…”

“…Several CCR5 polymorphisms have been described in human populations, some of which have been shown to affect CCR5 gene expression and function [11][12][13][14][15][16][17][18]. The distribution of CCR5 alleles already described varies among geographical areas and ethnic populations [17,19 -22].…”

CCL5-CCR5-mediated Apoptosis in T Cells

“…Accordingly, we focused on Tyr 339 to investigate its contribution as a potential site for recruitment of signaling effectors in mediating cell death. Dong et al (53) reported that whether HEK293 cells express intact CCR5 or the tyrosine mutant variant, CCR5Y339F, CCL5-receptor binding is unaffected. In agreement, we do not observe a defect in the kinetics of CCL5 binding or internalization in PM1.CCR5Y339F cells in response to CCL5 (data not shown).…”