# Defining the Bacteroidetes Type VI Secretion System MC-BP Interface and Regulation

> **NIH NIH F31** · DARTMOUTH COLLEGE · 2024 · $48,974

## Abstract

ABSTRACT
The human gastrointestinal tract is densely colonized by microorganisms which must compete in order to
survive. This competition dictates which microorganisms fill dominate roles in the microbiome, and in turn have
the strongest influence over host health. The Type VI Secretion System (T6SS) is a mechanism utilized by
Gram-negative members of the gut microbiota to compete. The T6SS functions by injecting toxic effectors in a
contact-dependent manner into recipient cells, resulting in target cell death and proliferation of attackers. T6SS
are employed by pathogenic invaders of the gut, such as Vibrio cholerae, as well as bacteria considered
healthy commensals. Two major phyla of bacterial residents in the gut employ T6SS, Proteobacteria and
Bacteroidetes. The Proteobacteria T6SS, designated T6SSi, has been well-studied over the past decade.
T6SSi activity is known to rely on the membrane complex, the transenvelope channel for effector translocation,
and the baseplate, the assembly hub and initiator of firing. The Bacteroidetes T6SS, T6SSiii, has been recently
reported by our group to encode a novel membrane complex, while retaining a structurally conserved
baseplate. How the baseplate could evolve a unique adaptor functionality to interact with a distinct membrane
complex is unknown. In addition, nothing is known regarding regulation of T6SSiii assembly, whether in
individual cells, a bacterial community, or a colonized mammalian GI tract.
This candidate will investigate the membrane complex-baseplate interface in Bacteroides fragilis (Aim 1), a
ubiquitous gut Bacteroidetes, as well as the T6SSiii regulation of assembly (Aim 2). Pursuit of these aims will
require training in new techniques, mentorship from experts in varied fields, enrichment of collaborative
networks, as well as strengthening and expansion of the candidate’s scientific and professional skills.
Ultimately, the candidate will receive support in entering the field of academia, and become better equipped to
teach and train others in that career path.

## Key facts

- **NIH application ID:** 10995586
- **Project number:** 1F31AI181533-01A1
- **Recipient organization:** DARTMOUTH COLLEGE
- **Principal Investigator:** Casey J Latario
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $48,974
- **Award type:** 1
- **Project period:** 2024-09-01 → 2026-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10995586

## Citation

> US National Institutes of Health, RePORTER application 10995586, Defining the Bacteroidetes Type VI Secretion System MC-BP Interface and Regulation (1F31AI181533-01A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10995586. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*