Studies

The ascorbate peroxidase APEX2 is commonly used to study the neighborhood of a protein of interest by proximity-dependent biotinylation. Here, we describe a protocol for sample processing compatible with immunoblotting and mass spectrometry that is suitable to specifically map the content of autophagosomes and potentially other transient vesicles without the need of subcellular fractionation. By combining live-cell biotinylation with proteinase K digestion of cell homogenates, proteins enriched ...

Autophagy is responsible for degradation of an extensive portfolio of cytosolic cargoes that are engulfed in autophagosomes to facilitate their transport to lysosomes. Besides basal autophagy, which constantly degrades cellular material, the pathway is dynamically altered by different conditions, resulting in enhanced autophagosome formation and cargo turnover. The extensive profile of autophagosome content as well as the phospholipid composition of human autophagosome membranes remains elusive. ...

To identify ubiquitylation targets following lysosomal damage in HeLa cells treated with LLOMe we performed quantitative ubiquitin-remmnant (diGly) profilig coupled to mass spectrometry (MS). In addition, we performed APEX2-based proximity biotinylation followed by MS analysis to identify proximity partners of one of the ubiquitylation targets (CNN2).

The founding member of the F-box protein family, Cyclin F, serves as substrate adaptor for the Ubiquitin E3 ligase Skp1-Cul1-F-box (SCF)Cyclin F which is responsible for ubiquitination of proteins involved in cell cycle progression, DNA damage and mitotic fidelity. Missense mutations in CCNF encoding for Cyclin F are associated with amyotrophic lateral sclerosis (ALS). However, it remains elusive whether CCNF mutations affect the substrate adaptor function of Cyclin F and whether altered SCFCyclin ...

In the project “Phosphoproteomic analysis of UBQLN2 mutant cells” by Laura Strohm, Zehan Hu, Jörn Dengjel, and Christian Behrends eight sets of SILAC experiments were performed, two times four biological replicates, comparing proteome and phosphoproteome of control and UBQLN2 mutant, patient-derived lymphoblasts (LCLs).

CD4+ T cells orchestrate both humoral and cytotoxic immune responses. While it is known that CD4+ T cell proliferation relies on autophagy, direct identification of the autophagosomal cargo involved is still missing. Here, we created a transgenic mouse model, which, for the first time, enables us to directly map the proteinaceous content of autophagosomes in any primary cell by LC3 proximity labelling. IL-7Rα, a cytokine receptor mostly found in naïve and memory T cells, was reproducibly detected ...

C9orf72 binds SMCR8 to from a robust complex that regulates small GTPases, lysosomal integrity and autophagy. In contrast to this functional understanding, we know far less about assembly and turnover of the C9orf72-SMCR8 complex. Loss of either subunit causes the concurrent ablation of the respective partner. However, the molecular mechanism underlying this interdependence remains elusive.