Binding of the rhesus TRIM5α PRYSPRY domain to capsid is necessary but not sufficient for HIV-1 restriction

Abstract

The PRYSPRY domain of TRIM5α provides specificity and the capsid recognition motif to retroviral restriction. Restriction of HIV-1 by rhesus TRIM5α (TRIM5αrh) has been correlated to its ability to bind to the HIV-1 core, suggesting that capsid binding is required for restriction. This work explores whether the PRYSPRY domain of TRIM5αrh exhibits an additional function besides binding to the HIV-1 core. Using our recently described structure of the PRYSPRY domain, we performed an exhaustive structure-function study of the surface and interior residues of the PRYSPRY domain. Testing retroviral restriction and capsid binding of an extensive collection of 60 TRIM5αrh PRYSPRY variants revealed that binding is necessary but not sufficient for restriction. In support of this hypothesis, we showed that some human tripartite motif proteins bind the HIV-1 capsid but do not restrict HIV-1 infection, such as human TRIM6 and TRIM34. Overall this work suggested that the PRYSPRY domain serves an unknown function, distinct from the binding of TRIM5αrh to the HIV-1 core, to block HIV-1 infection.

Restriction of HIV-1 Requires the N-Terminal Region of MxB as a Capsid-Binding Motif but Not as a Nuclear Localization Signal

“…In some cases, samples containing the MxB variants were diluted with extracts prepared in parallel from untransfected cells. To test binding, 5 l of capsid-nucleocapsid (CA-NC) complex particles assembled in vitro was incubated with 200 l of cell lysate at room temperature for 1 h (28,29). A fraction of this mixture was stored (input).…”

Contribution of MxB Oligomerization to HIV-1 Capsid Binding and Restriction

“…To understand the role of oligomerization in the ability of MxB to bind capsid, we tested the ability of interface 1, interface 2, and putative leucine zipper MxB variants to bind in vitro-assembled HIV-1 CA-NC complexes (Fig. 4 and Table 1) as described previously (26). MxB variants with mutations in interface 1 bound in vitro-assembled HIV-1 CA-NC complexes as strongly as the wild-type MxB (Fig.…”

Inhibition of microtubules and dynein rescues human immunodeficiency virus type 1 from owl monkey TRIMCyp-mediated restriction in a cellular context-specific fashion

“…Most of them also have an additional functional domain at the C terminus (Sardiello et al, 2008); in the case of TRIM5a, this additional domain is a PRYSPRY motif, also called SPRY or B30.2 (Song et al, 2005). The PRYSPRY domain is responsible for the specificity of restriction, by mediating direct interactions with surface patches present in the N-terminal region of retroviral CA proteins (Biris et al, 2013;Sebastian & Luban, 2005;Yang et al, 2014). In several independent instances, retrotransposition events have led to the insertion of the cyclophilin A (CypA)-coding sequence into the trim5 locus of New World or Old World primate species, leading to the expression of various TRIMCyp hybrid proteins.…”