# Latent TGF-β2 Structure and Activation

> **NIH NIH R01** · BOSTON CHILDREN'S HOSPITAL · 2024 · $692,334

## Abstract

Abstract. Transforming growth factor β2 (TGF-β2) is critically important for heart and vascular development
and repair. TGF-β2 dysregulation is seen in patient TGF-β2 mutations, systemic sclerosis, and Kawasaki
disease, which have cardiovascular sequelae such as aortic aneurysms and cardiac fibrosis. TGF-β1, 2 and 3
are synthesized as proproteins that dimerize and associate with milieu molecules that regulate TGF-β tissue
localization, such as the transmembrane protein glycoprotein A repetitions predominant (GARP) and latent
TGF-β binding proteins (LTBPs) in the extracellular matrix (ECM). Proconvertases cleave between the
prodomain and growth factor (GF) domain; however, the prodomain dimer remains non-covalently associated
with the GF in a proTGF-β–milieu molecule complex after secretion. ProTGF-β–milieu molecule complexes are
inactive because the prodomains encircle the GF and prevent binding to TGF-β receptors. ProTGF-β1 and 3
activation is mediated by binding of integrins αVβ6 and αVβ8 to an RGD-motif in the prodomain and requires
proTGF-β association with a milieu molecule. How proTGF-β2, which lacks an RGD-motif, is activated remains
a mystery. Aim 1 will define the structure of proTGF-β2 to understand its mechanism of latency. Aim 2 will
determine proTGF-β2/milieu molecule complex structures by X-ray crystallography and cryo-EM to define how
milieu molecules bind and alter TGF-β2 latency. We will generate antibodies to use as crystallization
chaperones in addition to using already developed nanobodies to proTGF-β2. Complementary unfolding
studies will test the hypothesis that milieu molecule binding stabilizes proTGF-β2. Aim 3 characterizes TGF-β2
activation. Follow-up studies will identify cell-lines that natively activate TGF-β2 and characterize the
physiologically relevant process. The results of this grant will enhance our understanding of TGF-β2 latency
and activation in extracellular milieus and lay the foundation for developing therapeutics that target proTGF-β2
and its physiologically relevant complexes with milieu molecules.

## Key facts

- **NIH application ID:** 10805527
- **Project number:** 5R01HL159714-08
- **Recipient organization:** BOSTON CHILDREN'S HOSPITAL
- **Principal Investigator:** TIMOTHY A SPRINGER
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $692,334
- **Award type:** 5
- **Project period:** 2022-04-01 → 2026-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10805527

## Citation

> US National Institutes of Health, RePORTER application 10805527, Latent TGF-β2 Structure and Activation (5R01HL159714-08). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10805527. Licensed CC0.

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