# Spatiotemporal regulation of bacterial cell envelope assembly

> **NIH NIH R35** · UNIVERSITY OF SOUTH FLORIDA · 2023 · $364,823

## Abstract

Project Summary/Abstract
Despite their small size, bacterial cells precisely synchronize cellular processes in space and time. The cell
envelopes of bacteria are complex and dynamic structures that are coordinately assembled during the cell cycle.
Cell wall anchored surface proteins of Gram-positive bacteria are major cell envelope components, which are
secreted across the cytoplasmic membrane and covalently attached to cell wall peptidoglycan by sortase A
(SrtA). Strikingly, many surface proteins contain a specific YSIRK/G-S signal peptide that targets proteins to the
cross-wall during cell division. Coordinated with cell division and cell wall synthesis, cross-wall targeting
promotes efficient incorporation of surface proteins to the newly synthesized cross-wall peptidoglycan; however,
the mechanisms remain unknown. It has been proposed that the YSIRK/G-S signal peptide promotes localized
secretion at the division septum. However, by developing a new microscopy method in our model organism of
Staphylococcus aureus, we now provide evidence that in contrast to the prevailing model, the targeting does not
occur during secretion, but rather is SrtA-dependent. We further discovered that cross-wall targeting is regulated
by another important cell envelope component: LtaS-mediated lipoteichoic acid (LTA) synthesis and D-
alanylation of teichoic acids. Intriguingly, LTA synthesis and D-alanylation regulate different biogenesis stages:
LTA regulates SrtA-mediated septal anchoring whereas D-alanylation modulates cross-wall deposition.
Collectively, these recent discoveries from my own lab form the foundation of my independent research program
for this MIRA application. We will elucidate the distinct mechanisms by which the YSIRK/G-S signal peptide, LTA
synthesis and D-alanylation spatially regulate surface protein biogenesis during the cell cycle. Successful
completion of the research projects will not only reveal novel mechanisms underlying surface protein biogenesis
in Gram-positive bacteria, but also uncover novel functions of LTA and D-alanylation in cell envelope assembly,
providing fundamental insight into how bacterial cells precisely coordinate cell envelope assembly during growth
and cell division.

## Key facts

- **NIH application ID:** 10707248
- **Project number:** 5R35GM146993-02
- **Recipient organization:** UNIVERSITY OF SOUTH FLORIDA
- **Principal Investigator:** Wenqi Yu
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $364,823
- **Award type:** 5
- **Project period:** 2022-09-20 → 2027-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10707248

## Citation

> US National Institutes of Health, RePORTER application 10707248, Spatiotemporal regulation of bacterial cell envelope assembly (5R35GM146993-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10707248. Licensed CC0.

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