Biology subjects

Daly, J. L.

Publications and source records attributed to Daly, J. L..

5 recordsLinked to original sources

bioRxiv2025

Identification of a VPS29 isoform with restricted association to Retriever and Retromer accessory proteins through auto-inhibition.

The endosomal-lysosomal network is a hub of organelles that orchestrate the dynamic sorting of hundreds of integral membrane proteins to maintain cellular homeostasis. VPS29 is a central conductor of this network through its assembly into Retromer, Retriever and Commander endosomal sorting complexes, and its role in regulating RAB GTPase activity. Two VPS29 isoforms have been described, VPS29A and VPS29B, that differ solely in their amino-terminal sequences. Here we identify a third VPS29 isoform, which we term VPS29C, that harbours an extended amino-terminal sequence compared to VPS29A and VPS29B. Through a combination of AlphaFold predictive modelling, in vitro complex reconstitution, mass spectrometry and molecular cell biology, we find that the amino-terminal VPS29C extension constitutes an autoinhibitory sequence that limits access to a hydrophobic groove necessary for effector protein recruitment to Retromer, and association with Retriever and Commander. VPS29C is therefore unique in its ability to uncouple Retromer-dependent cargo sorting from the broader roles of VPS29A and VPS29B in regulating the endosomal-lysosomal network through accessory protein recruitment. Our identification and characterisation of VPS29C points to additional complexity in the differential subunit assembly of Retromer, an important consideration given the increasing interest in Retromer as a potential therapeutic target in neurodegenerative diseases. SIGNIFICANCE STATEMENTThe endosomal-lysosomal network is essential for normal cellular function with network defects being associated with numerous neurodegenerative diseases. Two heterotrimeric complexes, Retromer and Retriever, control transmembrane protein recycling through the network. Of these, reduced Retromer expression is observed in Alzheimers disease and Retromer mutations lead to familial Parkinsons disease. Here, we identify and characterise a new isoform of VPS29, a subunit shared between Retromer and Retriever. We reveal how this isoform, VPS29C, adopts an auto-inhibitory conformation to limit its association into Retriever and restrict the binding of VPS29C-containing Retromer to accessory proteins vital for regulating network function. By revealing added complexity in Retromer assembly and function, we provide new insight into Retromers potential as a therapeutic target in neurodegenerative diseases.

cell biology↗

bioRxiv2022

Multiomic Approach Characterises the Neuroprotective Role of Retromer in Regulating Lysosomal Health

Retromer controls cellular homeostasis through regulating integral membrane protein sorting and transport and by controlling late-stage maturation of the endo-lysosomal network. Retromer dysfunction, which is linked to neurodegenerative disorders including Parkinsons and Alzheimers diseases, manifests in complex cellular phenotypes, though the precise nature of this dysfunction, and its relation to neurodegeneration, remain unclear. Here, we perform the first integrated multiomics approach to provide precise insight into the impact of Retromer dysfunction on endo-lysosomal health and homeostasis within a human neuroglioma cell model. We quantify profound changes to the lysosomal proteome, indicative of broad lysosomal dysfunction and inefficient autophagic lysosome reformation, coupled with a reconfigured cell surface proteome and secretome reflective of increased lysosomal exocytosis. Through this global proteomic approach and parallel transcriptomic analysis, we provide an unprecedented integrated view of Retromer function in regulating lysosomal homeostasis and emphasise its role in neuroprotection.

neuroscience↗

bioRxiv2022

ESCPE-1 Mediates Retrograde Endosomal Sorting of the SARS-CoV-2 Host Factor Neuropilin-1

Endosomal sorting maintains cellular homeostasis by recycling transmembrane proteins and associated proteins and lipids (termed cargoes) from the endosomal network to multiple subcellular destinations, including retrograde traffic to the trans-Golgi network (TGN). Viral and bacterial pathogens subvert retrograde trafficking machinery to facilitate infectivity. Here, we develop a proteomic screen to identify novel retrograde cargo proteins of the Endosomal SNX-BAR Sorting Complex Promoting Exit-1 (ESCPE-1). Using this methodology, we identify Neuropilin-1 (NRP1), a recently characterised host factor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, as a cargo directly bound and trafficked by ESCPE-1. ESCPE-1 mediates retrograde trafficking of engineered nanoparticles functionalised with the NRP1-interacting peptide of the SARS-CoV-2 Spike protein. ESCPE-1 sorting of NRP1 may therefore play a role in the intracellular membrane trafficking of NRP1-interacting viruses such as SARS-CoV-2.

cell biology↗

bioRxiv2020

Neuropilin-1 is a host factor for SARS-CoV-2 infection

SARS-CoV-2 is the causative agent of COVID-19, a coronavirus disease that has infected more than 6.6 million people and caused over 390,000 deaths worldwide1,2. The Spike (S) protein of the virus forms projections on the virion surface responsible for host cell attachment and penetration. This viral glycoprotein is synthesized as a precursor in infected cells and, to be active, must be cleaved to two associated polypeptides: S1 and S2(3,4). For SARS-CoV-2 the cleavage is catalysed by furin, a host cell protease, which cleaves the S protein precursor at a specific sequence motif that generates a polybasic Arg-Arg-Ala-Arg (RRAR) C-terminal sequence on S1. This sequence motif conforms to the C-end rule (CendR), which means that the C-terminal sequence may allow the protein to associate with cell surface neuropilin-1 (NRP1) and neuropilin-2 (NRP2) receptors5. Here we demonstrate using immunoprecipitation, site-specific mutagenesis, structural modelling, and antibody blockade that, in addition to engaging the known receptor ACE2, S1 can bind to NRP1 through the canonical CendR mechanism. This interaction enhances infection by SARS-CoV-2 in cell culture. NRP1 thus serves as a host factor for SARS-CoV-2 infection, and provides a therapeutic target for COVID-19.

cell biology↗

bioRxiv2019

Acute perturbation of retromer and ESCPE-1 leads to functionally distinct and temporally resolved defects in endosomal cargo sorting.

The human retromer is a stable heterotrimer of VPS35, VPS29 and VPS26 whose principal role is to orchestrate the endosomal retrieval of hundreds of internalised cargo and promote their recycling to the cell surface; a prototypical cargo being the glucose transporter GLUT1. Retromers role in a distinct endosomal retrieval pathway, the retrograde sorting of the cation-independent mannose 6-phosphate receptor (CI-MPR) to the trans-Golgi network (TGN), remains controversial. Here we have developed and applied knocksideways to acutely inactivate retromer and by visualising the sorting of endogenous GLUT1 and CI-MPR provide insight into the temporal dynamics of endosomal cargo sorting in HeLa and H4 human neuroglioma cells. While retromer knocksideways led to the development of time-resolved defects in cell surface sorting of GLUT1 we failed to observe defects in the sorting of the CI-MPR. In contrast knocksideways of ESCPE-1, a key regulator of retrograde CI-MPR sorting, resulted in a time-resolved defect in CI-MPR sorting. Together these data provide independent evidence consistent with a comparatively limited role for retromer in ESCPE-1 dependent CI-MPR retrograde sorting in HeLa and H4 human neuroglioma cells.

cell biology↗