Biology subjects

Futter, C.

Publications and source records attributed to Futter, C..

3 recordsLinked to original sources

bioRxiv2026

HRS dephosphorylation at membrane contact sites promotes sorting within multivesicular endosomes

HRS is a receptor tyrosine kinase substrate and component of the ESCRT machinery. It enables sorting of ubiquitylated cargo into multivesicular endosomes (MVEs) for lysosomal degradation but also functions in receptor recycling. We show that co-depletion of its ESCRT-0 binding partners, STAM1 and STAM2, recapitulates defects in EGF receptor (EGFR) sorting onto intraluminal vesicles (ILVs) but does not mirror the increased MVE size evident after HRS depletion. Using mutagenesis of the endogenous gene or introduction of APEX2-tagged HRS variants, we find that HRS Y329/334 phosphorylation is dispensable for EGFR sorting and MVE size control. AnnexinA1 mediates endosomal contact with the ER and promotes EGF-stimulated ILV formation. We show that reduced ILV formation on AnnexinA1 depletion is accompanied by increased HRS phosphorylation, likely through reduced HRS dephosphorylation by ER-localised PTP1B. Conversely, Y329/334 mutation renders ILV formation insensitive to AnnexinA1 depletion. Our data suggest that rapid HRS dephosphorylation at ER:MVE contacts promotes efficient ILV formation.

cell biology↗

bioRxiv2021

Fission of megamitochondria into multiple smaller well-defined mitochondria in the ageing zebrafish retina

Mitochondria are essential adenosine triphosphate (ATP)-generating cellular organelles. In the retina, they are highly numerous in the photoreceptors and retinal pigment epithelium (RPE) due to their high energetic requirements. Fission and fusion of the mitochondria within these cells allow them to adapt to changing demands over the lifespan of the organism. Using transmission electron microscopy, we examined the mitochondrial ultrastructure of zebrafish photoreceptors and RPE from 5 days post fertilisation (dpf) through to late adulthood (3 years). Notably, mitochondria in the youngest animals were large and irregular shaped with a loose cristae architecture, but by 8 dpf they had reduced in size and expanded in number with more defined cristae. When investigating temporal gene expression of several mitochondrial-related markers, they indicated fission as the dominant mechanism contributing to these changes observed over time. This is likely to be due to continued mitochondrial stress resulting from the oxidative environment of the retina and prolonged light exposure. We have characterised retinal mitochondrial ageing in a key vertebrate model organism, that provides a basis for future studies of retinal diseases that are linked to mitochondrial dysfunction.

cell biology↗

bioRxiv2020

Methamphetamine enhances caveolar transport of therapeutic drugs across the rodent blood-brain barrier

The blood-brain barrier (BBB) is a multifactorial and multicellular vascular interface separating the systemic environment from the central nervous system (CNS). It gates cerebral penetration of circulating molecules and cells and is the principal reason for low accumulation of many therapeutics in the brain. Low dose methamphetamine (METH) induces fluid phase transcytosis across the BBB in vitro and could therefore be used to enhance CNS drug delivery. Here we show, that low dose intravascular METH induced significant leakage exclusively via caveolar transport at the intact BBB in rodents ex vivo. Notably, METH-induced leakage was suppressed at 4{degrees}C and in Caveolin-1 (CAV1) knockout mice. Furthermore, METH strongly enhanced brain penetration of therapeutic molecules, namely doxorubicin (DOX), a small chemotherapeutic agent, and aflibercept (AFL), a ca. 100 kDA recombinant protein. Lastly, METH improved the therapeutic efficacy of DOX in a mouse model of human glioblastoma (GBM), as measured by a 25% increase in median survival time (p = 0.0024). Collectively, our data indicated that METH can facilitate preclinical assessment of novel experimental treatments and has the potential to enhance drug delivery to the diseased CNS.

neuroscience↗