Author Correction: The highly GABARAP specific rat monoclonal antibody 8H5 visualizes GABARAP in immunofluorescence imaging at endogenous levels.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The highly GABARAP specific rat monoclonal antibody 8H5 visualizes GABARAP in immunofluorescence imaging at endogenous levels.

The determination of unique functions of GABARAP (gamma-aminobutyric acid type A receptor-associated protein), a member of the highly conserved protein family of mammalian autophagy-related 8 protein (mATG8), within diverse cellular processes remains challenging. Because available anti-GABARAP antibodies perform inadequate, especially within various microscopy-based applications, we aimed to develop an antibody that targets GABARAP but not its close orthologs. Following the latest recommendations for antibody validation including fluorescence protein tagging, genetic and orthogonal strategies, we characterized the resulting anti-GABARAP (8H5) antibody during confocal immunofluorescence imaging in-depth. We compared the antibody staining pattern with that obtained for fluorescence protein tagged GABARAP, GABARAPL1 or GABARAPL2 each ectopically expressed in GABARAP knockout cells. Furthermore, we imaged cells expressing all mATG8 family members at endogenous levels and checked GABARAP knockout cells for unspecific staining under fed or macroautophagy-inducing conditions. Finally, we simultaneously stained cells for endogenous GABARAP and the common autophagosomal marker LC3B. Summarized, the presented antibody shows high specificity for GABARAP without cross-reactivity to other mATG8 family members in immunofluorescence imaging making it a valuable tool for the identification of unique GABARAP functions.

Zika virus NS2B/NS3 proteinase: A new target for an old drug - Suramin a lead compound for NS2B/NS3 proteinase inhibition.

Zika virus infection is the focus of much research due to the medical and social repercussions. Due the role of the viral NS2B/NS3 proteinase in maturation of the viral proteins, it had become an attractive antiviral target. Numerous investigations on viral epidemiology, structure and function analysis, vaccines, and therapeutic drugs have been conducted around the world. At present, no approved vaccine or even drugs have been reported. Thus, there is an urgent need to develop therapeutic agents to cure this epidemic disease. In the present study, we identified the polyanion suramin, an approved antiparasitic drug with antiviral properties, as a potential inhibitor of Zika virus complex NS2B/NS3 proteinase with IC50 of 47 µM. Using fluorescence spectroscopy results we could determine a kd value of 28 µM and had shown that the ligand does not affect the thermal stability of the protein. STD NMR spectroscopy experiments and molecular docking followed by molecular dynamics simulation identified the binding epitopes of the molecule and shows the mode of interaction, respectively. The computational analysis showed that suramin block the Ser135 residue and interact with the catalytically histidine residue.