Biology subjects

Guerin, G.

Publications and source records attributed to Guerin, G..

2 recordsLinked to original sources

bioRxiv2025

Asymmetric phosphoinositide lipid bilayers generated by spontaneous lipid insertion

Phosphatidylinositol phosphate (PIP) lipids, enriched on the cytoplasmic leaflet of the plasma membrane, are key regulators of diverse cellular processes, often through interactions with partner proteins that regulate actin assembly. Supported lipid bilayers (SLBs) provide a powerful model system to study the interactions of PIP lipids with their partner proteins. However, despite advances in SLB preparation methods, it remains a challenge to robustly obtain fluid SLBs in which PIP lipids are both mobile and asymmetrically distributed. In this study, we report a simple and robust method to generate asymmetric SLBs containing tunable amounts of PI(4,5)P2. By dissolving PI(4,5)P2 below its critical micelle concentration (CMC), we enable its spontaneous insertion into the upper leaflet of SLBs exposed to bulk solution. The mobility of PI(4,5)P2 is confirmed using fluorescence recovery after photobleaching (FRAP). Furthermore, we demonstrate that PI(4,5)P2 incorporated using this method retains its functionality, recruiting binding partners, actin-membrane linker ezrin, and myosin 1 motors capable of sliding actin filaments on the SLBs. Our method offers a straightforward strategy to generate asymmetric PI(4,5)P2-containing SLBs and is applicable to other lipid species with high CMC values.

biophysics↗

bioRxiv2023

On the Quina side: A Neanderthal bone industry at Chez-Pinaud site, France

Did Neanderthal produce a bone industry? The recent discovery of a large bone tool assemblage at the Neanderthal site of Chagyrskaya (Altai, Siberia, Russia) and the increasing discoveries of isolated finds of bone tools in various Mousterian sites across Eurasia stimulate the debate. Assuming that the isolate finds may be the tip of the iceberg and that the Siberian occurrence did not result from a local adaptation of easternmost Neanderthals, we looked for evidence of a similar industry in the Western side of their spread area. We assessed the bone tool potential of the Quina bone-bed level currently under excavation at chez Pinaud site (Jonzac, Charente-Maritime, France) and found as many bone tools as flint ones: not only the well-known retouchers but also beveled tools, retouched artifacts and a smooth-ended rib. Their diversity opens a window on a range of activities not expected in a butchering site and not documented by the flint tools, all involved in the carcass processing. The re-use of 20% of the bone blanks, which are mainly from large ungulates among faunal remains largely dominated by reindeer, raises the question of blank procurement and management. From the Altai to the Atlantic shore, through a multitude of sites where only a few objects have been reported so far, evidence of a Neanderthal bone industry is emerging which provides new insights on Middle Paleolithic subsistence strategies.

paleontology↗