PT  - JOURNAL ARTICLE
AU  - Yunxiao Zhang
AU  - Wan-Jin Lu
AU  - David P. Bulkley
AU  - Jiahao Liang
AU  - Arthur Ralko
AU  - Kelsey J. Roberts
AU  - Anping Li
AU  - Wonhwa Cho
AU  - Yifan Cheng
AU  - Aashish Manglik
AU  - Philip A. Beachy
TI  - Hedgehog pathway activation through conformational blockade of the Patched sterol conduit
AID  - 10.1101/783290
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 783290
4099  - http://biorxiv.org/content/early/2019/09/26/783290.short
4100  - http://biorxiv.org/content/early/2019/09/26/783290.full
AB  - Activation of the Hedgehog pathway may have therapeutic value for improved bone healing, taste receptor cell regeneration, and alleviation of colitis or other conditions. Systemic pathway activation, however, may be detrimental and therapeutic application has been difficult for lack of agents amenable to tissue targeting. We have developed a novel agonist, a conformation-specific nanobody against the Hedgehog receptor Patched1. This nanobody potently activates the Hedgehog pathway in vitro and in vivo by stabilizing an alternative conformation of a Patched1 “switch helix”, as revealed by cryo-EM structure determination. Although this conformation likely constitutes part of the transport cycle, nanobody-trapping disrupts the cycle and prevents substrate movement through the Patched1 sterol conduit. Our conformation-selective nanobody approach provides a new route to the development of transporter-related pharmacologic agents and may be generally applicable to the study of other transporters.