Lack of GABARAP-Type Proteins Is Accompanied by Altered Golgi Morphology and Surfaceome Composition.

GABARAP (γ-aminobutyric acid type A receptor-associated protein) and its paralogues GABARAPL1 and GABARAPL2 comprise a subfamily of autophagy-related Atg8 proteins. They are studied extensively regarding their roles during autophagy. Originally, however, especially GABARAPL2 was discovered to be involved in intra-Golgi transport and homotypic fusion of post-mitotic Golgi fragments.

Deficiency of GABARAP but not its Paralogs Causes Enhanced EGF-induced EGFR Degradation.

The γ-aminobutyric acid type A receptor-associated protein (GABARAP) and its close paralogs GABARAPL1 and GABARAPL2 constitute a subfamily of the autophagy-related 8 (Atg8) protein family. Being associated with a variety of dynamic membranous structures of autophagic and non-autophagic origin, Atg8 proteins functionalize membranes by either serving as docking sites for other proteins or by acting as membrane tethers or adhesion factors. In this study, we describe that deficiency for GABARAP alone, but not for its close paralogs, is sufficient for accelerated EGF receptor (EGFR) degradation in response to EGF, which is accompanied by the downregulation of EGFR-mediated MAPK signaling, altered target gene expression, EGF uptake, and EGF vesicle composition over time.

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 metalloproteinase ADAM15 is upregulated by shear stress and promotes survival of endothelial cells.

Reduced shear stress resulting from disturbed blood flow can impair endothelial integrity and drive the development of vascular inflammatory lesions. Metalloproteinases of the ADAM family have been implicated in the regulation of cell survival and inflammatory responses. Here we investigate the mechanism and function of ADAM15 upregulation in primary flow cultured endothelial cells.

Autophagy-Related Proteins GABARAP and LC3B Label Structures of Similar Size but Different Shape in Super-Resolution Imaging.

Subcellular structures containing autophagy-related proteins of the Atg8 protein family have been investigated with conventional wide-field fluorescence and single molecule localisation microscopy. Fusion proteins of GABARAP and LC3B, respectively, with EYFP were overexpressed in HEK293 cells. While size distributions of structures labelled by the two proteins were found to be similar, shape distributions appeared quite disparate, with EYFP-GABARAP favouring circular structures and elliptical structures being dominant for EYFP-LC3B.

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.