# The Role of LIMA1 in the Formation of the Giant Core Actin Bundles in Tuft Cells

> **NIH NIH F31** · VANDERBILT UNIVERSITY · 2024 · $34,314

## Abstract

PROJECT SUMMARY
Within the small intestinal epithelium, tuft cells are a rare chemosensory cell type (less than 1% of cells), defined
by their unique morphology consisting of large apical protrusions that extend over 2 μm into the lumen. Tuft cells
have been implicated in sensing intestinal parasites and activating an immune response and are therefore
recognized for their importance in maintaining the health of the intestinal epithelium. Tuft cell morphology is
defined by a unique cytoskeletal structure consisting of giant bundles of actin filaments, which support an array
of large apical membrane protrusions (a “tuft”) while extending over 6 μm down into the cell’s perinuclear region.
Despite their role in activating an immune response against intestinal parasites, tuft cells remain understudied
due to their rarity in the intestinal epithelium. As a result, there is a gap in our understanding of how the unique
cytoskeletal architecture found in tuft cells contributes to the physiological function of this cell type. My preliminary
research identified LIM domain and actin binding 1 (LIMA1) as a tuft cell enriched factor that localizes specifically
to the basal ends of core actin bundles that extend deep into the sub-apical cytoplasm. Previous studies indicate
that LIMA1 can cross-link actin, inhibit actin depolymerization, and inhibit actin branching in vitro, which are all
molecular activates that tuft cells could use to promote the formation of giant actin bundles. Based on my
preliminary data and previous studies in the literature, I hypothesize that LIMA1 drives the formation of the
giant actin bundles found in tuft cells. Under Aim 1, I will test this hypothesis by establishing how LIMA1
expression impacts the formation of actin bundles in an intestinal cell culture model. In addition, I will use live
cell imaging and Fluorescence Recovery After Photobleaching (FRAP) to characterize LIMA1 dynamics on actin
bundles and determine if LIMA1 expression impacts the dynamics of actin turnover in decorated bundles. In Aim
2, I will determine whether LIMA1 expression is required for tuft cell actin bundle formation. Because tuft cells
are not represented in intestinal epithelial cell culture models, I will instead use a LIMA1 knockout mouse model
and visualize de novo tuft cell development in the context of intestinal organoids derived from these animals.
This research seeks to develop a fundamental understanding of the molecular machinery underpinning the
unique morphology of tuft cell. The insights derived from this project will additionally help us understand how tuft
cells contribute to gastrointestinal physiology, immune sensing, and human health issues caused by intestinal
parasites and for inflammatory illnesses such as Crohn’s Disease.

## Key facts

- **NIH application ID:** 10997063
- **Project number:** 1F31DK141157-01
- **Recipient organization:** VANDERBILT UNIVERSITY
- **Principal Investigator:** Jennifer Silverman
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $34,314
- **Award type:** 1
- **Project period:** 2024-08-01 → 2026-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10997063

## Citation

> US National Institutes of Health, RePORTER application 10997063, The Role of LIMA1 in the Formation of the Giant Core Actin Bundles in Tuft Cells (1F31DK141157-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10997063. Licensed CC0.

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