# Sonic Hedgehog is a Calcium-regulated Zinc peptidase

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA BERKELEY · 2021 · $328,848

## Abstract

Hedgehog (Hh) signaling plays a central role during development in most animals, including mammals, while
aberrant activation of the Hh response is associated with common cancers. Hhs are synthesized as pro-proteins
that undergo an autoproteolytic event yielding the active N-terminal domain (HhN), and a C-terminal domain
(HhC). HhN has 3 domains: its N-terminus binds the Hh receptor Patched (Ptch), the middle domain binds
calcium (Ca) and the third domain coordinates zinc (Zn). The Ca- and Zn-binding domains (the bulk of HhN) are
up to 65% identical to some bacterial peptidases (BacHhs), including all residues predicted to mediate catalysis
and allosteric regulation. Many of these conserved residues are found mutated in holoprosencephaly, a
congenital birth defect, emphasizing their importance for normal Hh function. Preliminary studies show that the
peptidase activity intrinsic to Shh (a vertebrate Hh) is required for its release into the extracellular matrix (ECM)
and the supernatant and thus for non-cell autonomous signaling. The inclusion of Shh in a highly conserved
family of peptidases that spans multiple domains of life, combined with observations that the peptidase activity
of Shh is required for Shh distribution and signaling form the premise of the hypothesis that ShhN is a Ca-
regulated Zn-peptidase that mediates its release to allow non-cell autonomous signaling. Using Shh mutants in
addition to BacHh/Shh mosaics, Aim1 will examine Shh residues that are required for catalysis, substrate
recognition, and Ca regulation by assessing Shh distribution and signaling. Aim 2 will determine the substrates
of Shh-mediated catalysis. Two plausible, non-mutually exclusive, substrates for Shh are Shh itself, including the
removal of hydrophobic anchors or the release of the Ptch1-dinding domain, and ECM proteoglycans. In
particular, heparan sulphate proteoglycans (HSPGs) that affect Shh signaling and extracellular distribution are
assessed as substrates. Further characterization of the Shh-associated peptidase activity and identification of
substrates will have major ramification in understanding the role of Shh as a developmental morphogen and will
likely provide new targets to suppress non-cell autonomous Shh signaling that is a driving force in several
cancers.

## Key facts

- **NIH application ID:** 10119586
- **Project number:** 2R01GM117090-05A1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA BERKELEY
- **Principal Investigator:** HENK ROELINK
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $328,848
- **Award type:** 2
- **Project period:** 2016-02-01 → 2024-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10119586

## Citation

> US National Institutes of Health, RePORTER application 10119586, Sonic Hedgehog is a Calcium-regulated Zinc peptidase (2R01GM117090-05A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10119586. Licensed CC0.

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