Studies

The beta-secretase BACE1 is a central drug target for Alzheimer’s disease. Clinically tested, BACE1-directed inhibitors also block the homologous protease BACE2. Yet, little is known about physiological BACE2 substrates and functions in vivo. Here, we performed glycoprotein enrichment and subsequent discovery proteomics to identify substrates of the protease BACE2 in plasma of mice. Therefore, we analysed plasma from BACE2 KO, BACE1/2 double KO and WT controls, as well as BACE1 KO with a separate ...

In the context of studying the role of the COP9 signalosome (CSN) in neuroinflammation and ischemic neuronal damage, we studied the effect of the cullin NEDDylation state-modifying drugs MLN4924 and CSN5i-3 in BV2 microglial cells, an immortalized murine cell line featuring many of the characteristics of primary microglia. Owing to its potent inhibitory effect on the NEDDylation cascade, MLN4924 exhibits a CSN5-like anti-inflammatory activity. Csn5i-3 is a small molecule inhibitor that specifically ...

Chaperone-assisted selective autophagy (CASA) initiated by the cochaperone Bcl2-associated athanogene 3 (BAG3) represents an important mechanism for the disposal of misfolded and damaged proteins in mammalian cells. Under mechanical stress, the cochaperone cooperates with the small heat shock protein HSPB8 and the cytoskeleton-associated protein SYNPO2 to degrade force-unfolded forms of the actin-crosslinking protein filamin. This is essential for muscle maintenance in flies, fish, mice and men. ...

Signal peptide peptidase (SPP) and the four homologous SPP-like (SPPL) proteases constitute a family of intramembrane aspartyl proteases with selectivity for type II-oriented transmembrane segments. Here, we have analysed the physiological function of the orphan protease SPPL2c, previously considered to represent a non-expressed pseudogene. We identified proteolytic activity of SPPL2c towards selected tail-anchored proteins. Despite shared ER localization, SPPL2c and SPP exhibit distinct, though ...

Description

Proteolytic ectodomain shedding of membrane proteins is a fundamental mechanism to control the communication between cells and their environment. A key protease for membrane protein shedding is ADAM17, which requires a non-proteolytic subunit, either inactive Rhomboid 1 (iRhom1) or iRhom2 for its activity. While iRhom1 and iRhom2 are coexpressed in most tissues and appear to have largely redundant functions, the brain is an organ with predominant expression of iRhom1. Yet, little is ...

A disintegrin and metalloprotease 10 (ADAM10) is essential for embryonic development and impacts on diseases such as cancer, Alzheimer’s and inflammatory diseases. ADAM10 is a ‘molecular scissor’ that proteolytically cleaves the extracellular region from over 100 substrates, including Notch, amyloid precursor protein, cadherins, growth factors and chemokines. ADAM10 was recently proposed to function as six distinct scissors with different substrates, depending on its association with one of six ...

The autophagic clearance of damaged lysosomes by lysophagy involves extensive modification of the organelle with ubiquitin, but the underlying ubiquitination machinery is still poorly characterized. Here, we use an siRNA screening approach and identify human UBE2QL1 as a major regulator of lysosomal ubiquitination, lysophagy, and cell survival after lysosomal damage. UBE2QL1 translocates to permeabilized lysosomes where it associates with damage sensors, ubiquitination targets, and lysophagy ...