Stephan Müller

Loss-of-function mutations in CLN3 cause juvenile Batten disease, featuring neurodegeneration and early-stage neuroinflammation. How loss of CLN3 function leads to early neuroinflammation is not yet understood. Here, we have comprehensively studied microglia from Cln3∆ex7/8 mice, a genetically accurate disease model. Loss of CLN3 function in microglia leads to lysosomal storage material accumulation and abnormal morphology of subcellular organelles. Moreover, pathological proteomic signatures are ...

Ubiquitin carboxyl-terminal hydrolase 19 (USP19) is a unique deubiquitinase, characterized by multiple variants generated by alternative splicing. Several variants bear a C-terminal transmembrane domain that anchors them to the endoplasmic reticulum. Other than regulating protein stability by preventing proteasome degradation, USP19 has been reported to rescue substrates from endoplasmic reticulum-associated protein degradation in a catalytic-independent manner, promote autophagy, and address ...

Ectodomain shedding, which is the proteolytic release of transmembrane proteins from the cell surface, is crucial for cell-to-cell communication and other biological processes. The metalloproteinase ADAM17 mediates ectodomain shedding of over 50 transmembrane proteins ranging from cytokines and growth factors, such as TNF and EGFR ligands, to signalling receptors and adhesion molecules. Yet, the ADAM17 sheddome is only partly defined and biological functions of the protease have not been fully ...

Proteins delivered by endocytosis or autophagy to lysosomes are degraded by exo- and endoproteases. In humans 15 lysosomal cathepsins (CTS) act as important physiological regulators. The cysteine proteases CTSB and CTSL and the aspartic protease CTSD are the most abundant and functional important lysosomal proteinases. Whereas their general functions in proteolysis in the lysosome, their individual substrate, cleavage specificity, and their possible sequential action on substrate proteins have ...

Loss-of-function mutations in the homotrimeric serine protease HTRA1 cause cerebral vasculopathy. Here, we establish independent approaches to achieve the functional correction of trimer assembly defects. Focusing on the prototypical R274Q mutation, we identify an HTRA1 variant that promotes trimer formation thus restoring enzymatic activity in vitro. Genetic experiments in Htra1R274Q mice further demonstrate that expression of this protein-based corrector in trans is sufficient to stabilize ...