Biology subjects

Smith, G. P.

Publications and source records attributed to Smith, G. P..

5 recordsLinked to original sources

bioRxiv2026

Rapid removal of nuclear aggregates via proteasome- and VCP-dependent disaggregation

Cells use multiple protein quality control (PQC) mechanisms to counteract the toxic effects of protein aggregation caused by cellular stress, ageing or disease. While it is known that PQC mechanisms differ between cellular compartments, studying such differences has remained challenging. Previously, we developed an assay to study cytosolic PQC using aggregates formed through chemically-induced dimerization (termed PIMs, particles induced by multimerization). Here, we introduce nuclear PIMs as a tool to study nuclear quality control. Using high-resolution and high-throughput imaging, we show that nuclear aggregate removal depends on the proteasome and the unfoldase VCP, but not on Hsp70. Strikingly, following dissolution many PIM subunits were exported to the cytosol via exportin-1-dependent shuttling, indicating that disaggregation and resolubilization dominated over degradation. Proteasomal disaggregation was confirmed using live-cell turnover experiments. Together, these findings reveal a mechanism in which the proteasome and VCP disaggregate, rather than degrade, nuclear protein aggregates, with the resulting subunits subsequently cleared via cytosolic aggrephagy.

cell biology↗

bioRxiv2023

Multi-modal skin atlas associates a multicellular immune-stromal community with altered cornification and T cell expansion in atopic dermatitis

In healthy skin, a cutaneous immune system maintains the balance between tolerance towards innocuous environmental antigens and immune responses against pathological agents. In atopic dermatitis (AD), barrier and immune dysfunction result in chronic tissue inflammation. Our understanding of the skin tissue ecosystem in AD remains incomplete with regard to the hallmarks of pathological barrier formation, and cellular state and clonal composition of disease-promoting cells. Here, we generated a multi-modal cell census of 310,691 cells spanning 86 cell subsets from whole skin tissue of 19 adult individuals, including non-lesional and lesional skin from 11 AD patients, and integrated it with 396,321 cells from four studies into a comprehensive human skin cell atlas in health and disease. Reconstruction of human keratinocyte differentiation from basal to cornified layers revealed a disrupted cornification trajectory in AD. This disrupted epithelial differentiation was associated with signals from a unique immune and stromal multicellular community comprised of MMP12+ dendritic cells (DCs), mature migratory DCs, cycling ILCs, NK cells, inflammatory CCL19+ IL4I1+ fibroblasts, and clonally expanded IL13+IL22+IL26+ T cells with overlapping type 2 and type 17 characteristics. Cell subsets within this immune and stromal multicellular community were connected by multiple inter-cellular positive feedback loops predicted to impact community assembly and maintenance. AD GWAS gene expression was enriched both in disrupted cornified keratinocytes and in cell subsets from the lesional immune and stromal multicellular community including IL13+IL22+IL26+ T cells and ILCs, suggesting that epithelial or immune dysfunction in the context of the observed cellular communication network can initiate and then converge towards AD. Our work highlights specific, disease-associated cell subsets and interactions as potential targets in progression and resolution of chronic inflammation.

molecular biology↗

bioRxiv2020

Quantifying the impacts of urban human-wildlife conflicts - how can we solve the urban gull problem in St Andrews?

Interactions between urban wildlife and people are increasing globally. Some of these interactions can be negative and lead to human-wildlife conflicts. In St Andrews, Scotland, residents and business owners have come into conflict with herring gulls (Larus argentatus) and lesser black-backed gulls (Larus fuscus) that nest and forage in the town. This study quantified the number, species and distribution of nesting gulls; the vulnerability of different sources of rubbish to attack; and the likelihood of negative human-gull interactions related to food. Surveys were conducted in St Andrews during the 2016 breeding season (May-July). Nesting gull density and distribution were estimated during weekly street surveys of buildings; vantage surveys were conducted for some buildings and a correction factor estimating a minimum number of nesting gulls was produced. 110 nesting gull pairs were estimated and these occupied ~10% of buildings. The vulnerability of waste sources to attack was monitored during transects recording whether or not rubbish sources were attacked. Black bin bags had the highest probability of being attacked, but placing these in secured hessian bags prevented this. The frequency of negative human-gull interactions involving food at street-level was determined during 10-minute timed watches at various locations. Incidences of gulls taking food were rare; only eight were seen in 30 hours of watches. Altering human behaviour (for example, disposing of waste securely) will mitigate potential issues with urban wildlife. Findings from this study will enable effective management of human-gull conflicts in St Andrews and have potential applications in other urban communities.

ecology↗

bioRxiv2018

Long-term exposure to PFE-360 in the AAV-α-synuclein rat model: findings and implications

Significance statementTreatment of Parkinsons disease is reliant on symptomatic treatments, without any option to slow or halt disease progression. Mutations in LRRK2 and -synuclein are known risk factors for Parkinsons disease. Presence of -synuclein aggregates at autopsies in both idiopathic and most G2019S cases is suggestive of a common disease pathogenesis. LRRK2 and -synuclein interaction is hypothesized to play a pivotal role in the pathological mechanisms and inhibitors of LRRK2 are investigated as novel disease modulatory treatments in the clinic. However, preclinical in vivo evidence of a beneficial effect of LRRK2 inhibition is mixed and limited. This study increases our understanding of LRRK2 as a mediator of neuronal dysfunction and the potential of LRRK2 as a promising target in PD.

neuroscience↗

bioRxiv2018

LRRK2 exonic variants associated with Parkinson’s disease augment phosphorylation levels for LRRK2-Ser1292 and Rab10-Thr73

Leucine-rich repeat kinase 2 (LRRK2) is associated to Parkinsons disease (PD). The most common form of LRRK2 PD is caused by the G2019S variant. Besides G2019S, eight other LRRK2 variants causing familial PD also have amino acid substitutions located in a LRRK2 enzymatic domainsuggesting that enzymatic activity is at the core of mechanisms underlying disease risk. Common LRRK2 polymorphic risk variations such as G2385R, A419V, R1628 and M1646T all reside in other LRRK2 domains. Prior knowledge is limited on how these variants influence LRRK2 function. To investigate the impact on enzymatic function of both rare and common LRRK2 variation a comprehensive profiling of nineteen LRRK2 exonic variants was pursued. Six LRRK2 phosphorylation sites were identified by mass spectrometry. Besides already known phosphorylation sites such as Ser910, Ser935, Ser955, Ser973 and Ser1292 also Thr826 was confirmed by a targeted MRM assay as a LRRK2 phosphorylation site in mammalian cells. Phosphorylation site occupancy for all six LRRK2 sites was obtained but no obvious correlation to risk of disease was found. Instead, application of phospho-specific antibodies targeting LRRK2 phosphorylation sites confirmed that autophosphorylation at Ser1292 was significantly increased for all disease-causing variants whereas no significant differences could be observed for the common intermediate risk variants. Recently, Rab10 and Rab12 have been shown to be bona fide LRRK2 substrates and we find that both rare and common LRRK2 exonic variants augment the phosphorylation of Rab10. This was not observed with Rab12. Furthermore, the protective variant N551K has reduced Rab10 phosphorylation compared to LRRK2 WT. This was not observed with the protective variant R1398H. Our findings support the hypothesis that increased LRRK2 kinase function is associated with increased PD risk but also highlights the need for more sensitive tools for detection of increases in kinase activity in carriers of LRRK2 PD risk variants.\n\nAbbreviations

biochemistry↗