Biology subjects

Lautenschlaeger, J.

Publications and source records attributed to Lautenschlaeger, J..

3 recordsLinked to original sources

bioRxiv2023

VAMP2 regulates phase separation of alpha-synuclein

SummaryAlpha-synuclein (aSYN) is a small synaptic protein that is linked to Parkinsons disease (PD) and other synucleinopathies. aSYN has been shown to undergo protein phase separation. We found that aSYN phase separation, in vitro and in cells, is regulated by vesicle-associated membrane protein 2 (VAMP2), the vesicular SNARE protein. We show that aSYN phase separation is promoted by C-terminal electrostatic interaction, which in cells is mediated via interaction with VAMP2. The condensate formation is specific for the R-SNARE VAMP2 and critically dependent on aSYNs capacity to bind to lipid membranes. In vitro, the addition of VAMP2 decreases the saturation concentration of aSYN phase separation, which is mediated by its juxtamembrane domain. Our results delineate a molecular mechanism for the regulation of aSYN phase separation, indicating a potential switch from the dispersed to the phase-separated state during vesicle cycling. HighlightsO_LIAlpha-synuclein phase separation is regulated by electrostatic interactions C_LIO_LIVAMP2 initiates alpha-synuclein condensation in cells C_LIO_LIPositive charges within the juxtamembrane domain of VAMP2 initiate alpha-synuclein phase separation in vitro C_LIO_LIAlpha-synuclein condensates nucleate on lipid membranes and assemble vesicular structures in cells C_LI

cell biology↗

bioRxiv2020

Dodecin as carrier protein for immunizations and bioengineering applications

In bioengineering, scaffold proteins have been increasingly used to recruit molecules to parts of a cell, or to enhance the efficacy of biosynthetic or signaling pathways. For example, scaffolds can be used to make weak or non-immunogenic small molecules immunogenic by attaching them to the scaffold, in this role called carrier. Here, we present the dodecin from Mycobacterium tuberculosis (mtDod) as a new scaffold protein. MtDod is a homododecameric complex of spherical shape, high stability and robust assembly, which allows the attachment of cargo at its surface. We show that mtDod, either directly loaded with cargo or equipped with domains for non-covalent and covalent loading of cargo, can be produced recombinantly in high quantity and quality in Escherichia coli. Fusions of mtDod with proteins of up to four times the size of mtDod, e.g. with monomeric superfolder green fluorescent protein creating a 437 kDa large dodecamer, were successfully purified, showing mtDods ability to function as recruitment hub. Further, mtDod equipped with SYNZIP and SpyCatcher domains for post-translational recruitment of cargo was prepared of which the mtDod/SpyCatcher system proved to be particularly useful. In a case study, we finally show that mtDod peptide fusions allow producing antibodies against human heat shock proteins and the C-terminus of heat shock cognate 70 interacting protein (CHIP). For Table of Contents Only O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=111 SRC="FIGDIR/small/990861v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@1b30641org.highwire.dtl.DTLVardef@5fa8bdorg.highwire.dtl.DTLVardef@3f16a3org.highwire.dtl.DTLVardef@1e756a5_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2019

Intra-mitochondrial protein degradationalleviates alpha-synuclein seeding and Abeta 42 aggregation

Mitochondria have long been implicated in Parkinsons disease (PD), however, it is not clear how mitochondrial impairment and alpha-synuclein pathology are coupled. We report here that intra-mitochondrial protein homeostasis plays a major role in alpha-synuclein fibril elongation, as interference with intra-mitochondrial proteases and mitochondrial protein import significantly aggravate alpha-synuclein aggregation. In contrast, direct inhibition of mitochondrial complex I, increase in intracellular calcium concentration or formation of reactive oxygen species (ROS), all of which have been associated with mitochondrial stress, did not affect alpha-synuclein pathology. We further demonstrate that similar mechanisms are involved in Amyloid {beta} 1-42 (A{beta}42) aggregation, suggesting that mitochondria are directly capable of influencing cytosolic protein homeostasis of aggregation-prone proteins.

neuroscience↗