PT  - JOURNAL ARTICLE
AU  - Fabio Lolicato
AU  - Roberto Saleppico
AU  - Alessandra Griffo
AU  - Bianca Pokrandt
AU  - Hans-Michael Müller
AU  - Helge Ewers
AU  - Hendrik Hähl
AU  - Jean-Baptiste Fleury
AU  - Ralf Seemann
AU  - Britta Brügger
AU  - Karin Jacobs
AU  - Ilpo Vattulainen
AU  - Walter Nickel
TI  - Cholesterol promotes both head group visibility and clustering of PI(4,5)P&lt;sub&gt;2&lt;/sub&gt; driving unconventional secretion of Fibroblast Growth Factor 2
AID  - 10.1101/2021.04.16.440132
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.04.16.440132
4099  - http://biorxiv.org/content/early/2021/04/16/2021.04.16.440132.short
4100  - http://biorxiv.org/content/early/2021/04/16/2021.04.16.440132.full
AB  - Fibroblast Growth Factor 2 (FGF2) is a cell survival factor involved in tumor-induced angiogenesis. FGF2 is secreted through an unconventional secretory pathway based upon direct protein translocation across the plasma membrane. Here we demonstrate that both PI(4,5)P2-dependent FGF2 recruitment at the inner plasma membrane leaflet and FGF2 membrane translocation into the extracellular space are positively modulated by cholesterol in living cells. We further reveal cholesterol to enhance FGF2 binding to PI(4,5)P2-containing lipid bilayers in a fully reconstituted system. Based on extensive atomistic molecular dynamics simulations and membrane tension experiments, we propose cholesterol to modulate FGF2 binding to PI(4,5)P2 by (i) increasing head group visibility of PI(4,5)P2 on the membrane surface, (ii) increasing avidity by cholesterol-induced clustering of PI(4,5)P2 molecules triggering FGF2 oligomerization and (iii) increasing membrane tension facilitating the formation of lipidic membrane pores. Our findings have general implications for phosphoinositide-dependent protein recruitment to membranes and explain the highly selective targeting of FGF2 towards the plasma membrane, the subcellular site of FGF2 membrane translocation during unconventional secretion of FGF2.Competing Interest StatementThe authors have declared no competing interest.