Calcium-dependent and -independent lipid transfer mediated by tricalbins in yeast

Abstract

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Manganese promotes α-synuclein amyloid aggregation through the induction of protein phase transition

“…Recombinant untagged α-Syn was expressed in Escherichia coli and purified by nickel affinity chromatography, using a previously established procedure ( 79 , 80 , 81 , 82 ). The human α-Syn gene was cloned into a pET28a-based SUMO vector.…”

“…The turbidity was employed to evaluate the protein phase separation. The samples were added to a transparent 96-well plate in a turbidity assay, and the absorbance at 405 nm was measured at 37 °C using a BioTek Synergy HT microplate reader ( 80 ). Full accounting of statistical significance was included for each figure based on at least three independent experiments.…”

Mechanisms of Non-Vesicular Exchange of Lipids at Membrane Contact Sites: Of Shuttles, Tunnels and, Funnels

“…SMP domains are exclusively associated with MCSs ( Toulmay and Prinz, 2012 ; Jeyasimman and Saheki, 2020 ); however, ERMES is not found in Metazoans and seems mostly restricted to yeasts and fungi ( Wideman et al, 2013 ). SMP domains were found in yeast tricalbins ( Manford et al, 2012 ; Qian et al, 2021 ), the orthologs of Extended Synaptotagmin proteins (E-SYTs) in Vertebrates ( Saheki and De Camilli, 2017 ) at ER-to-PM junctions ( Fernández-Busnadiego et al, 2015 ) and also in PDZ domain-containing protein 8 (PDZD8), first at ER-to-mitochondria ( Hirabayashi et al, 2017 ) then at ER-to-late endosome/lysosomes interfaces ( Guillén-Samander et al, 2019 ; Elbaz-Alon et al, 2020 ; Shirane, 2020 ; Shirane et al, 2020 ) also in Vertebrates. PDZD8 thus appears to be a shared component at a three-way MCS between ER, mitochondria and, late endosomes.…”

Membrane Contact Sites in Yeast: Control Hubs of Sphingolipid Homeostasis

“…Among the ER-PM tethering proteins the tricalbins seem to be possible candidates to drive this process since they have been suggested before as calcium effector proteins. Tricalbins feature several C2 calcium-binding domains [90] and possess cross membrane phospholipid transfer capabilities that are increased in the presence of calcium [106]. In addition, cells lacking Tcb1/2/3 display only a small reduction in ER-PM association but show strong defects in PM integrity following heat shock, which induces calcium signaling [90].…”