HIV-1 infection of T cells and macrophages are differentially modulated by virion-associated Hck: a Nef-dependent phenomenon

All-Round Manipulation of the Actin Cytoskeleton by HIV

While significant progress has been made in terms of human immunodeficiency virus (HIV) therapy, treatment does not represent a cure and remains inaccessible to many people living with HIV. Continued mechanistic research into the viral life cycle and its intersection with many aspects of cellular biology are not only fundamental in the continued fight against HIV, but also provide many key observations of the workings of our immune system. Decades of HIV research have testified to the integral role of the actin cytoskeleton in both establishing and spreading the infection. Here, we review how the virus uses different strategies to manipulate cellular actin networks and increase the efficiency of various stages of its life cycle. While some HIV proteins seem able to bind to actin filaments directly, subversion of the cytoskeleton occurs indirectly by exploiting the power of actin regulatory proteins, which are corrupted at multiple levels. Furthermore, this manipulation is not restricted to a discrete class of proteins, but rather extends throughout all layers of the cytoskeleton. We discuss prominent examples of actin regulators that are exploited, neutralized or hijacked by the virus, and address how their coordinated deregulation can lead to changes in cellular behavior that promote viral spreading.

Brain-specific HIV Nef identified in multiple patients with neurological disease

HIV-1 Nef is a flexible, multifunctional protein with several cellular targets that is required for pathogenicity of the virus. This protein maintains a high degree of genetic variation among intra- and inter-host isolates. HIV Nef is relevant to HIV-associated neurological diseases (HAND) in patients treated with combined antiretroviral therapy because of the protein's role in promoting survival and migration of infected brain macrophages. In this study, we analyzed 2020 HIV Nef sequences derived from 22 different tissues and 31 subjects using a novel computational approach. This approach combines statistical regression and evolved neural networks (ENNs) to classify brain sequences based on the physical and chemical characteristics of functional Nef domains. Based on training, testing, and validation data, the method successfully classified brain Nef sequences at 84.5% and provided informative features for further examination. These included physicochemical features associated with the Src-homology-3 binding domain, the Nef loop (including the AP-2 Binding region), and a cytokine-binding domain. Non-brain sequences from patients with HIV-associated neurological disease were frequently classified as brain, suggesting that the approach could indicate neurological risk using blood-derived virus or for the development of biomarkers for use in assay systems aimed at drug efficacy studies for the treatment of HIV-associated neurological diseases.

Understanding the Multifaceted Role of Human Down Syndrome Kinase DYRK1A

The dual-specificity tyrosine (Y) phosphorylation-regulated kinase DYRK1A, also known as Down syndrome (DS) kinase, is a dosage-dependent signaling kinase that was originally shown to be highly expressed in DS patients as a consequence of trisomy 21. Although this was evident some time ago, it is only in recent investigations that the molecular roles of DYRK1A in a wide range of cellular processes are becoming increasingly apparent. Since initial knowledge on DYRK1A became evident through minibrain mnb, the Drosophila homolog of DYRK1A, this review will first summarize the scientific reports on minibrain and further expand on the well-established neuronal functions of mammalian and human DYRK1A. Recent investigations across the current decade have provided rather interesting and compelling evidence in establishing nonneuronal functions for DYRK1A, including its role in infection, immunity, cardiomyocyte biology, cancer, and cell cycle control. The latter part of this review will therefore focus in detail on the emerging nonneuronal functions of DYRK1A and summarize the regulatory role of DYRK1A in controlling Tau and α-synuclein. Finally, the emerging role of DYRK1A in Parkinson's disease will be outlined.

A high throughput RNAi screen reveals determinants of HIV-1 activity in host kinases

Drug resistance remains a great challenge in HIV/AIDS treatment despite the recent advances in novel therapeutics. It may be a good strategy to develop drugs targeting the essential host factors to decrease the risk of drug resistance. Previous studies suggested that so many host kinases play roles in HIV life cycles. More importantly, many kinase genes are drugable targets, therefore, it is vital to figure out host kinases responsible for HIV-1 infection and replication to provide novel therapeutic regimens and to deepen our understanding to HIV-host interaction. In present work, a high throughput RNAi screen with a shRNA library against 474 kinases was applied to HEK293T cells stably expressed a HIV-1 LTR (long terminal repeat)-driven reporter plasmid. Four genes, AK1, EphB2, PRKACB and CDK5R2, were found to specifically suppress the HIV-1 LTR activity following effective knockdown. Furthermore, overexpression of AK1 and PRKACB upregulated the HIV-1 LTR activity. Therefore, AK1 and PRKACB are in positive control of HIV-1 activity. DNA microarray analysis demonstrated that overlapped genes between AK1-silenced and PRKACB-silenced cells were mainly enriched in several amino acid biosynthesis pathways, TGF-β signaling and p53 signaling pathways. These alterations may repress the viral infection by the downregulation of ERK1/2, p38MAPK and NFκB signaling pathways. Collectively, our work uncovers several host kinases involving the HIV-1 infection and may provide potential therapeutic targets for AIDS treatment in future.