Biology subjects

Laursen, L.

Publications and source records attributed to Laursen, L..

4 recordsLinked to original sources

bioRxiv2022

A syntenin inhibitor blocks endosomal entry of SARS-CoV-2 and a panel of RNA viruses

Viruses are dependent on interactions with host factors in order to efficiently establish an infection and replicate. Targeting such interactions provides an attractive strategy to develop novel antivirals. Syntenin is a protein known to regulate the architecture of cellular membranes by its involvement in protein trafficking, and has previously been shown to be important for HPV infection. Here we show that a highly potent and metabolically stable peptide inhibitor that binds to the PDZ1 domain of syntenin inhibits SARS-CoV-2 infection by blocking the endosomal entry of the virus. Furthermore, we found that the inhibitor also hampered chikungunya infection, and strongly reduced flavivirus infection, which are completely dependent on receptor mediated endocytosis for their entry. In conclusion, we have identified a novel pan-viral inhibitor that efficiently target a broad range of RNA viruses.

biochemistry↗

bioRxiv2021

Polarized α-synuclein trafficking and transcytosis across Brain Endothelial Cells via Rab7-decorated carriers

Parkinsons disease is mainly caused by aggregation of -synuclein (-syn) in the brain. Exchange of -syn between the brain and peripheral tissues could have important pathophysiological and therapeutic implications, but the trafficking mechanism of -syn across the blood brain barrier (BBB) remains unclear. In this study, we therefore investigated uptake and transport mechanisms of -syn monomers and oligomers across an in vitro BBB model system. Both -syn monomers and oligomers were internalized by primary brain endothelial cells, with increased restriction of oligomeric over monomeric transport. To enlighten the trafficking route of monomeric -syn in brain endothelial cells, we investigated co-localization of -syn and intracellular markers of vesicular transport. Here, we observed the highest colocalization with clathrin, Rab7 and VPS35, suggesting a clathrin-dependent internalization, preferentially followed by a late endosome retromer-connected trafficking pathway. Furthermore, STED microscopy revealed monomeric -syn trafficking via Rab7-decorated carriers. Knockdown of Caveolin1, VPS35, and Rab7 using siRNA did not affect monomeric -syn uptake into endothelial cells. However, it significantly reduced transcytosis of monomeric -syn in the luminal-abluminal direction, suggesting a polarized regulation of monomeric -syn vesicular transport. Our findings suggest a direct role for Rab7 in polarized trafficking of monomeric -syn across BBB endothelium, and the potential of Rab7 directed trafficking to constitute a target pathway for new therapeutic strategies against Parkinsons disease and related synucleinopathies. Significance StatementIn the submitted manuscript, we describe the use of a state-of-the-art porcine blood-brain barrier model based on primary cells to get information about this important issue. We identify several hitherto undescribed cellular pathways to mediate polarized transport of alpha-synuclein. One of these paths we find regulated by Rab7 and can be inhibited by targeting several intracellular proteins such as VPS35, Caveolin1 and Rab7. New knowledge describing brain endothelial intracellular transport systems are highly warranted for identifying new target to alleviate Parkinsons disease. We believe that our findings could be the seed to establish new therapeutic strategies against Parkinsons disease and related synucleinopathies.

cell biology↗

bioRxiv2020

Divergent evolution of a protein-protein interaction revealed through ancestral sequence reconstruction and resurrection

The postsynaptic density extends across the postsynaptic dendritic spine with Discs large (DLG) as the most abundant scaffolding protein. DLG dynamically alters the structure of the postsynaptic density, thus controlling the function and distribution of specific receptors at the synapse. PDZ domains make up one of the most abundant protein interaction domain families in animals. One important interaction governing postsynaptic architecture is that between the PDZ3 domain from DLG and cysteine-rich interactor of PDZ3 (CRIPT). However, little is know regarding functional evolution of the PDZ3:CRIPT interaction. Here, we subjected PDZ3 and CRIPT to ancestral sequence reconstruction, resurrection and biophysical experiments. We show that the PDZ3:CRIPT interaction is an ancient interaction, which was present in the last common ancestor of Eukaryotes, and that high affinity is maintained in most extant animal phyla. However, affinity is low in nematodes and insects, raising questions about the physiological function of the interaction in species from these animal groups. Our findings demonstrate how an apparently established protein-protein interaction involved in cellular scaffolding in bilaterians can suddenly be subject to dynamic evolution including possible loss of function.

molecular biology↗

bioRxiv2020

Supertertiary protein structure affects an allosteric network

The notion that protein function is allosterically regulated by structural or dynamic changes in proteins has been extensively investigated in several protein domains in isolation. In particular, PDZ domains have represented a paradigm for these studies, despite providing conflicting results. Furthermore, it is still unknown how the association between protein domains in supramodules, consitituting so-called supertertiary structure, affects allosteric networks. Here, we experimentally mapped the allosteric network in a PDZ:ligand complex, both in isolation and in the context of a supramodular structure, and show that allosteric networks in a PDZ domain are highly dependent on the supertertiary structure in which they are present. This striking sensitivity of allosteric networks to presence of adjacent protein domains is likely a common property of supertertiary structures in proteins. Our findings have general implications for prediction of allosteric networks from primary and tertiary structure and for quantitative descriptions of allostery.

biophysics↗