# New pharmacological tools to explore platelet GPR56 function

> **NIH NIH F31** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2020 · $37,520

## Abstract

Platelets are small cell fragments that circulate in the blood and their activation is critical for the
blood clotting response. Initial platelet activation results from interactions with the collagen sub-
layer that becomes exposed to the blood stream following blood vessel injury. Patients who have
platelets with impaired receptiveness to collagen have severe bleeding disorders. Recently, we
discovered that GPR56 (ADGRG1), a collagen-sensitive adhesion G protein-coupled receptor
(AGPCR), is present on the surface of platelets and mediates their activation mechanism.
AGPCRs are an understudied 33-member subfamily of GPCRs characterized in part by a bulky
extracellular domain. Knowledge of how AGPCRs operate in vivo has stagnated due to a lack of
available probe compounds. Consequently, I am finishing up large high throughput screens to
identify novel small molecule activators and inhibitors of GPR56. Use of these compounds will
expand our knowledge of both platelet biology and the AGPCR mechanism through my
pharmacological investigation of GPR56 signaling in platelets. I propose two aims to advance
knowledge of how GPR56 works in the platelet system: (1) Validate the new GPR56 activators
and inhibitors found in my screens, and (2) utilize GPR56-specific compounds to assess how
GPR56 mediates platelet signaling. Aim 1 will be accomplished using a battery of established
cell-based and biochemical assays to measure GPR56 signaling. Aim 2 will examine the effects
of GPR56 modulatory compounds in ex vivo human and mouse platelet assays. Blood clotting
(thrombosis) is implicated in a large portion of deaths. My studies will not only provide critical
insight into how blood clotting is regulated, but may also yield new classes of lead compounds
that might be used to treat hematological diseases.

## Key facts

- **NIH application ID:** 9991052
- **Project number:** 1F31HL152563-01
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Alexander Vizurraga
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $37,520
- **Award type:** 1
- **Project period:** 2020-05-01 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9991052

## Citation

> US National Institutes of Health, RePORTER application 9991052, New pharmacological tools to explore platelet GPR56 function (1F31HL152563-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9991052. Licensed CC0.

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