# "The molecular mechanisms of asymmetric cell division in mycobacteria."

> **NIH NIH R01** · YALE UNIVERSITY · 2022 · $417,839

## Abstract

Abstract
Tuberculosis (TB), a bacterial infection caused by Mycobacterium tuberculosis (Mtb), is now the leading cause
of death by a single infectious agent. One reason for this is that subpopulations of Mtb cells can survive even
lengthy chemotherapy, preventing cure of disease. These surviving cells are phenotypically tolerant, but not
genetically resistant, to antibiotic therapy. Thus, the ability of genetically identical bacteria to display different
phenotypes is a significant obstacle for the treatment of TB. A better understanding of the molecular
mechanisms underlying this phenomenon could lead to therapeutic advances for TB and other mycobacterial
infections. Much of the heterogeneity begins at mycobacterial cell division. Every time a mycobacterium
divides it produces daughters with different characteristics. We have recently discovered that this process is
genetically encoded. Deleting a single gene, which we have named lamA, leads to cells that grow and divide
more symmetrically and are more uniformly susceptible to certain antibiotics. The function of LamA and how it
mediates asymmetric growth and division are unknown. Here, we propose to investigate the molecular
function of LamA. Our published and preliminary data show that LamA localizes to the site of division, where it
inhibits the maturation of the new growth poles. In addition, we have connected LamA to the phosphorylation
state of an essential peptidoglycan synthase, and have discovered that its own localization is regulated by
phosphorylation. This leads to our hypothesis that LamA dynamically interrupts an unknown communication
relay between the multi-protein complexes that accomplish division and elongation, in a phosphorylation-
dependent manner. To test this model, we propose the following aims: (1) define the communication relay
between the division and elongation complexes; and, (2) dynamically map the regulatory events that lead to
asymmetry. Our innovation is to study a mycobacterial-specific protein that creates heterogeneity in a
genetically identical population. We will do so by leveraging our expertise in advanced imaging techniques in
combination with more traditional methods. Successful completion of these aims will lead to hypotheses about
the function of LamA that can be tested with molecular and biochemical approaches. Further, our results will
advance our understanding of the molecular basis of cell-division mediated heterogeneity, which has far-
reaching consequences for the treatment of TB. For example, identifying the molecular mechanism(s) that
leads to subpopulations of bacteria better able to survive antibiotic therapy will allow us to design drug
strategies that target heterogeneity. Such interventions could treat TB more quickly, something that would
greatly help reduce the global burden of TB disease.

## Key facts

- **NIH application ID:** 10401858
- **Project number:** 5R01AI148255-03
- **Recipient organization:** YALE UNIVERSITY
- **Principal Investigator:** Elizabeth Hesper Rego
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $417,839
- **Award type:** 5
- **Project period:** 2020-05-12 → 2025-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10401858

## Citation

> US National Institutes of Health, RePORTER application 10401858, "The molecular mechanisms of asymmetric cell division in mycobacteria." (5R01AI148255-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10401858. Licensed CC0.

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