# Mechanisms of mammalian Wnt5a-Ror signaling

> **NIH NIH R01** · BAYLOR COLLEGE OF MEDICINE · 2024 · $426,237

## Abstract

PROJECT SUMMARY/ABSTRACT
The Wnt5a-Ror signaling pathway is essential for embryonic tissue morphogenesis. Disruption of Wnt5a-Ror
signaling results in birth defects such as Robinow syndrome and Brachydactyly Type B, and is frequently
implicated in cancer metastasis and inflammatory disorders. The Wnt5a protein is palmitoleoylated at a
conserved serine, a unique feature shared by all the Wnt ligands, which require the GPCR-like protein Wntless
to transport their lipid-modified mature forms from the endoplasmic reticulum to the plasma membrane for
secretion. In contrast to the canonical Wnts whose mechanisms are relatively well characterized, Wnt5a signals
noncanonically through the ROR family of receptor tyrosine kinases (ROR1/2), which is independent of the
transcriptional factor β-catenin. Despite its physiological and pathological importance, the mechanisms of Wnt5a-
Ror signaling remain poorly understood. The major unanswered questions include how Wnt5a is secreted, how
Wnt5a activates RORs and how active RORs transduce Wnt5a signals to the cytoplasm. In preliminary work, we
determined a Cryo-EM structure of Wnt5a in complex with Wntless that reveals an unanticipated feature of Wnt5a
with important implications for its non-canonical function. We showed that purified extracellular domain (ECD) of
ROR2 promotes Wnt5a secretion, together with the recent crystal structure of Drosophila ROR2 ECD bound with
palmitoleic acid, suggesting that ROR2 directly recognizes the Wnt5a lipid. In addition, we developed a
peroxidase APEX2-catalyzed proximity labeling approach, and by quantitative multiplexed proteomics, we
demonstrated that for the first time, the recruitment of the downstream effector protein Dishevelled (DVL) to the
ROR receptors is exclusively dependent on Wnt5a stimulation. Based on these results, we propose to combine
biochemistry, structural, cell biology and proteomic studies to accomplish the following aims: A) To characterize
how Wntless transports Wnt5a, and how Wntless is recycled after Wnt5a secretion; B) To determine how Wnt5a
binds and activates the ROR receptors; and C) To elucidate how active ROR receptors trigger the downstream
cytoplasmic signaling events. These studies will have high impacts for the following reasons: 1) They will
advance our mechanistic understanding of Wnt5a-Ror signaling; 2) They will help explain the pathogenesis of
human diseases caused by abnormal Wnt5a-Ror signaling; 3) They will facilitate the therapeutic discoveries by
providing novel targets and strategies to treat Wnt5a-associated cancers; and 4) The APEX2-catalyzed proximity
labeling and proteomic approach that we developed will have broad applications to study signal transduction
pathways beyond Wnt5a-Ror signaling.

## Key facts

- **NIH application ID:** 10898023
- **Project number:** 5R01GM150878-02
- **Recipient organization:** BAYLOR COLLEGE OF MEDICINE
- **Principal Investigator:** Pengxiang Huang
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $426,237
- **Award type:** 5
- **Project period:** 2023-08-15 → 2027-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10898023

## Citation

> US National Institutes of Health, RePORTER application 10898023, Mechanisms of mammalian Wnt5a-Ror signaling (5R01GM150878-02). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10898023. Licensed CC0.

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