# NLRP1 and CARD8 Inflammasomes:  Assembly, Regulation and Stress Sensing

> **NIH NIH R01** · BOSTON CHILDREN'S HOSPITAL · 2021 · $531,000

## Abstract

Abstract
Nucleotide-binding domain (NBD)-like and leucine-rich repeat (LRR)-containing proteins (NLRs)
perform diverse functions in cellular biology, mediating a broad set of fundamental biological
pathways from immune signaling to embryonic development. In immunity, several NLRs form
supramolecular protein signaling complexes called inflammasomes. Inflammasomes activate
caspase-1, an inflammatory protease that processes the cytokine interleukin-1β (IL-1β) and the
pore-forming protein gasdermin D to potentiate pyroptotic cell death. One such inflammasome-
forming protein, NLRP1, is directly activated in response to intracellular pathogens and the
inhibition of DPP9, an endogenous peptidase, serving as both a pattern recognition receptor
and a signaling complex. While most NLRs share a common domain architecture, the
multifunctionality and regulation of NLRP1 requires additional structural components.
 In addition to the characteristic NBD and LRR domains, human NLRP1 contains an N-
terminal pyrin domain (PYD) and a rare function-to-find domain (FIIND) followed by a caspase
activation and recruitment domain (CARD) on its C-terminus. The only other protein with a
FIIND is CARD8, which has also been shown to form inflammasomes, leading to cytokine
secretion and cell death. Mechanistically, the NLRP1 and CARD8 FIIND domains constitutively
catalyze autoproteolytic cleavage, leading to the formation of two noncovalently associated
peptides: an autoinhibitory N-terminal fragment and an inflammatory C-terminal fragment.
Additionally, Dipeptidyl peptidase 8 or 9 (DPP8/9) binds and inhibits NLRP1 and CARD8, and
small molecule inhibitors of DPP8/9 induces NLRP1 and CARD8 activation through some poorly
understood pathway. In this application, we propose to elucidate the activation and regulation of
NLRP1 and CARD8 using a structure-guided approach. We will determine structures of NLRP1
or CARD8 in complex with DPP8 or DPP9, both WT and mutants. We will analyze the structures
and perform additional biochemical and cellular biological experiments to test our hypotheses.
In one central aim, we propose that NLRP1 and CARD8 are stress sensors for endogenous
cellular dysregulation and play important roles in unwanted inflammation and diseases.

## Key facts

- **NIH application ID:** 10122344
- **Project number:** 2R01AI124491-06
- **Recipient organization:** BOSTON CHILDREN'S HOSPITAL
- **Principal Investigator:** Hao Wu
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $531,000
- **Award type:** 2
- **Project period:** 2016-07-01 → 2026-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10122344

## Citation

> US National Institutes of Health, RePORTER application 10122344, NLRP1 and CARD8 Inflammasomes:  Assembly, Regulation and Stress Sensing (2R01AI124491-06). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10122344. Licensed CC0.

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