# Control of Antifungal Drug Tolerance through the Aspergillus fumigatus Kinome

> **NIH NIH R21** · UNIVERSITY OF TENNESSEE HEALTH SCI CTR · 2020 · $190,000

## Abstract

Invasive aspergillosis, caused mainly by A. fumigatus, is the most prevalent invasive mold infection of
immunocompromised individuals and is associated with mortality rates of 35-90%. Therapy options are
extremely limited for invasive aspergillosis and resistance to the triazole class of antifungals is on the rise.
Significant knowledge gaps concerning how A. fumigatus adapts to drug-induced stress (i.e., drug tolerance)
impair our ability to improve antifungal therapy and halt the rise in resistance. Our central hypothesis is that
protein phosphorylation events orchestrate cellular processes crucial for A. fumigatus triazole antifungal
tolerance. To delineate novel roles for the A. fumigatus kinome in triazole tolerance, we have completed a
preliminary phospho-proteomics analysis of the response to voriconazole treatment. Our preliminary data
reveal significant changes in the phosphorylation status of ~1400 proteins, implying extensive kinase-mediated
adaptation to drug-induced stress. Filtering this dataset for proteins known to mediate triazole tolerance, we
identified voriconazole-induced phosphorylation state changes in HapB. The HapB protein is a subunit of the
heterotrimeric CCAAT-binding complex (CBC), a crucial transcriptional repressor of ergosterol biosynthesis
genes. Interestingly, clinical triazole resistance in select A. fumigatus isolates has been ascribed to mutations
that alter functionality of the CBC. Therefore, delineation of CBC regulatory mechanisms could lead to novel
interventions targeting antifungal tolerance and/or resistance. In Aim 1, we will test the working hypothesis that
CBC-mediated regulation of triazole tolerance is controlled by differential phosphorylation of the HapB subunit.
In Aim 2, we will identify novel protein kinases supporting antifungal fitness in A. fumigatus using our novel
CRISPR/Cas9 mutational approach. Through these aims, we expected to uncover multiple, novel contributions
of protein kinases to A. fumigatus antifungal fitness. In addition, we will potentially delineate a phospho-
regulatory mechanism controlling the CBC, a crucial transcriptional regulator of the triazole stress response. As
they are considered the second largest class of proteins currently functioning as drug targets, identification of
the protein kinases crucial to triazole tolerance could reveal novel targets for use in new stand-alone or
combination therapies. Therefore, the potential impact of this work is the improvement of antifungal therapy
and significant advance towards the sustained clinical utility of triazole antifungals against Aspergillus.

## Key facts

- **NIH application ID:** 9822174
- **Project number:** 5R21AI142509-02
- **Recipient organization:** UNIVERSITY OF TENNESSEE HEALTH SCI CTR
- **Principal Investigator:** Jarrod R. Fortwendel
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $190,000
- **Award type:** 5
- **Project period:** 2018-11-13 → 2021-10-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9822174

## Citation

> US National Institutes of Health, RePORTER application 9822174, Control of Antifungal Drug Tolerance through the Aspergillus fumigatus Kinome (5R21AI142509-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9822174. Licensed CC0.

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