Lentivirus-associated MAPK/ERK2 phosphorylates EMD and regulates infectivity

Abstract

Infection of a cell by lentiviruses, such as human immunodeficiency virus type 1 or feline immunodeficiency virus, results in the formation of a reverse transcription complex, the preintegration complex (PIC), where viral DNA is synthesized. In non-dividing cells, efficient nuclear translocation of the PIC requires the presence of the inner nuclear lamina protein emerin (EMD). Here, we demonstrate that EMD phosphorylation is induced early after infection in primary nondividing cells. Furthermore, we demonstrate that EMD phosphorylation is dependent on virionassociated mitogen-activated protein kinase (MAPK). Specific inhibition of MAPK activity with kinase inhibitors markedly reduced EMD phosphorylation and resulted in decreased integration of the proviral DNA into chromatin. Similarly, when a MEK1 kinase-inactive mutant was expressed in virus-producer cells, virus-induced phosphorylation of EMD was impaired and viral integration reduced during the subsequent infection. Expression of constitutively active MEK1 kinase in producer cells did not result in modulation of EMD phosphorylation or viral integration during subsequent infection. These studies demonstrate that, in addition to phosphorylating components of the PICs at an early step of infection, virion-associated MAPK plays a role in facilitating cDNA integration after nuclear translocation through phosphorylation of target-cell EMD.

Cellular and viral determinants of retroviral nuclear entry

“…Particularly, MAPK binds with the virion and induces Gag-MA phosphorylation (Cartier et al 1997;Bukong et al 2010). Inhibition of these 2 proteins in macrophages causes a reduction in EMD phosphorylation and viral integration, affecting the viral infection (Bukong et al 2010). Therefore, these proteins are likely directly or indirectly related to each other and required for HIV-1 PIC import, at least in a cell-specific manner.…”

“…Moreover, upon viral infection, EMD is phosphorylated, which is dependent on both mitogen-activated protein kinase (MAPK) and MEK1 kinase (Bukong et al 2010). Particularly, MAPK binds with the virion and induces Gag-MA phosphorylation (Cartier et al 1997;Bukong et al 2010). Inhibition of these 2 proteins in macrophages causes a reduction in EMD phosphorylation and viral integration, affecting the viral infection (Bukong et al 2010).…”

“…Intriguingly, lentiviruses and oncoretroviruses may use LAP␣ throughout their life cycle, but EMD is required for lentiviruses (Jacque and Stevenson 2006). Moreover, upon viral infection, EMD is phosphorylated, which is dependent on both mitogen-activated protein kinase (MAPK) and MEK1 kinase (Bukong et al 2010). Particularly, MAPK binds with the virion and induces Gag-MA phosphorylation (Cartier et al 1997;Bukong et al 2010).…”

Emerin in health and disease

“…Known modifiers include the serine/threonine kinases protein kinase A (PKA; [184]), GSK3β [200], PKCδ [201], and ERK2/MAPK [202]. Emerin is also phosphorylated on multiple tyrosines by Src (Y59, Y74, Y95) [188], Abl (Y167) [188] and Her2 [188,203].…”

Mechanism of Host Cell MAPK/ERK-2 Incorporation into Lentivirus Particles: Characterization of the Interaction between MAPK/ERK-2 and Proline-Rich-Domain Containing Capsid Region of Structural Protein Gag

“…2,34,47,49 It was also shown that phosphorylation of viral proteins by the virion-associated kinases plays an important role in the regulation of early steps in viral replication. 2,8,9,33,49,62,66 Recent reports from our laboratory and others demonstrated that host cell serine-threonine kinases such as mitogen-activated protein kinase (MAPK)/extracellular signalregulated kinase 2 (ERK-2) and the catalytic subunit of cyclic AMP-dependent protein kinase A (C-PKA) are incorporated within HIV-1/SIV particles. 12,27,30,33,49 Interestingly, the structural protein Gag MA (HIV-1/SIV), capsid (CA), p6, Vpr (HIV-1), and Vpx (SIV) have been reported as the substrates for the virion-associated MAPK/ERK-2.…”