FEZ1 Is Recruited to a Conserved Cofactor Site on Capsid to Promote HIV-1 Trafficking

Abstract

Highlights d Kinesin adaptor protein FEZ1 directly interacts with HIV-1 capsid for trafficking d FEZ1 specifically targets the conserved center pore of capsid protein (CA) hexamers d FEZ1 uses electrostatic interactions to bind multiple CA hexamers in the capsid d FEZ1 capsid-binding residues are important for HIV-1 trafficking and infectivity SUMMARYHIV-1 uses the microtubule network to traffic the viral capsid core toward the nucleus. Viral nuclear trafficking and infectivity require the kinesin-1 adaptor protein FEZ1. Here, we demonstrate that FEZ1 directly interacts with the HIV-1 capsid and specifically binds capsid protein (CA) hexamers. FEZ1 contains multiple acidic, poly-glutamate stretches that interact with the positively charged central pore of CA hexamers. The FEZ1-capsid interaction directly competes with nucleotides and inositol hexaphosphate (IP6) that bind at the same location. In addition, all-atom molecular dynamic (MD) simulations establish the molecular details of FEZ1-capsid interactions. Functionally, mutation of the FEZ1 capsid-interacting residues significantly reduces trafficking of HIV-1 particles toward the nucleus and early infection. These findings support a model in which the central capsid hexamer pore is a general HIV-1 cofactor-binding hub and FEZ1 serves as a unique CA hexamer pattern sensor to recognize this site and promote capsid trafficking in the cell.

Primate lentiviruses require Inositol hexakisphosphate (IP6) or inositol pentakisphosphate (IP5) for the production of viral particles

“…When the viral core is depleted of IP6 in vitro , it breaks down more readily. Thus it has been inferred that after fusion with the target cell, IP6/IP5-lacking virus cannot effectively reverse transcribe the viral RNA to DNA [ 29 , 39 ]. To test if IP6 in the target cell is required for susceptibility to infection, we infected HEK293FT or IPPK-KO cells with virus produced from either HEK293FT or IPPK-KO cells and compared infection levels.…”

“…Mature HIV-1 particles use IP6 to stabilize the Fullerene cone capsid structure. IP6 also has been implicated in hexamer pore interactions with dNTPs, required for reverse transcription, and for trafficking to the nuclear envelope [10,29,30,39]. Therefore, it seemed possible that IP6 and IP5 levels could affect these viral interactions during viral entry, and thus cell susceptibility to infection.…”

Microtubule Retrograde Motors and Their Role in Retroviral Transport

“…While a newly arrived HIV-1 particle presents a retrograde net movement, live cell imaging has shown displays of bi-directional movement on microtubules [23,31,39]. In fact, FEZ1, the kinesin-1 heavy chain adaptor, regulates the early transport of incoming viral particles by associating to the HIV-1 capsid [31,40]. This confirmed the tug-of-war model, wherein both anterograde and retrograde transport of cargo takes place, although the net movement is retrograde.…”

Recent Advances in HIV-1 Gag Inhibitor Design and Development

“…Core stability is essential for viral replication, and due to its high conservation, mutations that stabilize or destabilize the core result in altered infectivity [83]. The viral core undergoes uncoating by interacting with various host cell proteins such as dyneins, the kinesin-1 adaptor FEZ1, and transportin-1; however, also partly dissembled structures can be found at the nuclear pore gates [84][85][86][87][88]. Host cell restriction factors have also been shown to recognize CA such as MxB [89,90], TRIM5a [91] and TRIMCyp [92], which accelerates uncoating and release of viral DNA, which can be sensed by other restriction factors such as the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) [93].…”