Patched 1 reduces the accessibility of cholesterol in the outer leaflet of membranes

Maia Kinnebrew, Giovanni Luchetti, Ria Sircar, Sara Frigui, Lucrezia Vittoria Viti, Tomoki Naito, Francis Beckert, Yasunori Saheki, Christian Siebold, Arun Radhakrishnan, Rajat Rohatgi

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


A long-standing mystery in vertebrate Hedgehog signaling is how Patched 1 (PTCH1), the receptor for Hedgehog ligands, inhibits the activity of Smoothened, the protein that transmits the signal across the membrane. We previously proposed (Kinnebrew et al., 2019) that PTCH1 inhibits Smoothened by depleting accessible cholesterol from the ciliary membrane. To directly test the effect of PTCH1 on accessible cholesterol, we measured the transport activity of PTCH1 using an imaging-based assay to follow the kinetics of cholesterol extraction from the plasma membrane of live cells by methyl-β-cyclodextrin. PTCH1 depletes accessible cholesterol in the outer leaflet of the membrane in a manner regulated by its ligand Sonic Hedgehog and the transmembrane potassium gradient. We propose that PTCH1 moves cholesterol from the outer to the inner leaflet of the membrane in exchange for potassium ion export. Our results show that proteins can change accessible cholesterol levels in membranes to regulate signaling reaction.

Original languageEnglish (US)
Article numbere70504
StatePublished - Oct 2021

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)


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