The γ-aminobutyric acid type A receptor-associated protein (GABARAP) and its close paralogs GABAR... more 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. We further show that GABARAP and EGFR converge in the same distinct compartments at endogenous GABARAP expression levels in response to EGF stimulation. Furthermore, GABARAP associates with EGFR in living cells and binds ...
An amendment to this paper has been published and can be accessed via a link at the top of the pa... more An amendment to this paper has been published and can be accessed via a link at the top of the paper.
CRISPR-mediated genome editing enables to study disease-relevant mutations. Next Generation Seque... more CRISPR-mediated genome editing enables to study disease-relevant mutations. Next Generation Sequencing offers high throughput and accuracy but requires substantial investment. Nanopore sequencing on the other hand provides cheap entry. Here, we describe our work using sequencing techniques to identify edited cells, analyze mitochondrial DNA, and gene expression. Finally, we describe how our software tools CRISPRnano and Duesselpore aid to democratize the use of modern sequencing technologies.
GABARAP (γ-aminobutyric acid type A receptor-associated protein) and its paralogues GABARAPL1 and... more 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. Recently, a broader function of mammalian Atg8s on membrane trafficking through interaction with various soluble N-ethylmaleimide-sensitive factor-attachment protein receptors (SNAREs) was suggested. By immunostaining and microscopic analysis of the Golgi network, we demonstrate the importance of the presence of individual GABARAP-type proteins on Golgi morphology. Furthermore, triple knockout (TKO) cells lacking the whole GABARAP subfamily showed impaired Golgi-dependent vesicular trafficking as assessed by imaging of fluorescently labelled ceramide. With the Golgi apparatus being central within the secr...
Enhanced glucose transport capacity of the intestinal epithelium, specifically enterocytes, is kn... more Enhanced glucose transport capacity of the intestinal epithelium, specifically enterocytes, is known to significantly contribute to systemic glucocorticoid (GC) - induced hyperglycemia. This effect is mainly dependent on overexpression of sodium glucose transporter 1 (Sglt1) and its enhanced activation by serum and glucocorticoid-regulated kinase 1 (Sgk1). In this work we aimed to investigate whether dietary intake affects intestinal glucocorticoid receptor (Nr3c1) signaling. In male C57/BL6 mice short term feeding of a Western diet (WD) resulted in increased glucocorticoid receptor expression in the ileum which was accompanied by an upregulation of the effector genes Sgk1 and sodium-hydrogen exchanger 3 (Nhe3) and liver receptor homologe 1 (Lrh1). The latter is known as the key regulator of intestinal corticosterone synthesis. Histological analysis showed that glucocorticoid receptor expression was mainly located in enterocytes. Intestinal Sgk1 expression remained significantly, ab...
The γ-aminobutyric acid type A receptor-associated protein (GABARAP) and its close paralogs GABAR... more 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. We further show that GABARAP and EGFR converge in the same distinct compartments at endogenous GABARAP expression levels in response to EGF stimulation. Furthermore, GABARAP associates with EGFR in living cells and binds ...
An amendment to this paper has been published and can be accessed via a link at the top of the pa... more An amendment to this paper has been published and can be accessed via a link at the top of the paper.
CRISPR-mediated genome editing enables to study disease-relevant mutations. Next Generation Seque... more CRISPR-mediated genome editing enables to study disease-relevant mutations. Next Generation Sequencing offers high throughput and accuracy but requires substantial investment. Nanopore sequencing on the other hand provides cheap entry. Here, we describe our work using sequencing techniques to identify edited cells, analyze mitochondrial DNA, and gene expression. Finally, we describe how our software tools CRISPRnano and Duesselpore aid to democratize the use of modern sequencing technologies.
GABARAP (γ-aminobutyric acid type A receptor-associated protein) and its paralogues GABARAPL1 and... more 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. Recently, a broader function of mammalian Atg8s on membrane trafficking through interaction with various soluble N-ethylmaleimide-sensitive factor-attachment protein receptors (SNAREs) was suggested. By immunostaining and microscopic analysis of the Golgi network, we demonstrate the importance of the presence of individual GABARAP-type proteins on Golgi morphology. Furthermore, triple knockout (TKO) cells lacking the whole GABARAP subfamily showed impaired Golgi-dependent vesicular trafficking as assessed by imaging of fluorescently labelled ceramide. With the Golgi apparatus being central within the secr...
Enhanced glucose transport capacity of the intestinal epithelium, specifically enterocytes, is kn... more Enhanced glucose transport capacity of the intestinal epithelium, specifically enterocytes, is known to significantly contribute to systemic glucocorticoid (GC) - induced hyperglycemia. This effect is mainly dependent on overexpression of sodium glucose transporter 1 (Sglt1) and its enhanced activation by serum and glucocorticoid-regulated kinase 1 (Sgk1). In this work we aimed to investigate whether dietary intake affects intestinal glucocorticoid receptor (Nr3c1) signaling. In male C57/BL6 mice short term feeding of a Western diet (WD) resulted in increased glucocorticoid receptor expression in the ileum which was accompanied by an upregulation of the effector genes Sgk1 and sodium-hydrogen exchanger 3 (Nhe3) and liver receptor homologe 1 (Lrh1). The latter is known as the key regulator of intestinal corticosterone synthesis. Histological analysis showed that glucocorticoid receptor expression was mainly located in enterocytes. Intestinal Sgk1 expression remained significantly, ab...
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