# Regulation of Mitochondrial Metabolism by Tyr-phosphorylated ATP Synthase Alpha-Subunit and its Therapeutic Implications in Prostate Cancer

> **NIH NIH R01** · WASHINGTON UNIVERSITY · 2024 · $439,433

## Abstract

Project Abstract
Cancer cell mitochondria switch their metabolic phenotypes to meet the challenges of high-energy demand and
macromolecular synthesis. Acute dependence of tumors on oncogenic tyrosine kinase signaling support their
rapid proliferation, however, direct relevance of the kinase activity for mitochondria to support these high-energy
processes remains obscure. Serendipitously, we uncovered that a non-receptor tyrosine kinase, ACK1,
phosphorylates ATP synthase F1 α-subunit (ATP5F1a) at Tyr243 and Tyr246 (Tyr200 & 203 in mature protein,
respectively) that increased ATP synthase activity specifically in the cancer cells. Mechanistically, ATP5F1a-
phosphorylation not only excluded its binding to its physiological inhibitor, ATPase Inhibitory Factor 1 (IF1), but
also created a supporting structure that extended from the bound non-catalytic nucleotide to the surface,
reducing the flexibility and thereby increasing the stability of the enzyme. A new class of ACK1 inhibitor, (R)-9b
reversed this process, inducing mitophagy and mitigating tumor growth. Consistently, a marked increase in
ATP5F1a-phosphorylations was observed as normal prostate progressed to the malignant stage. Overall, these
data provide the molecular evidence for cancer cell `mitochondrial addiction’ to Tyr-kinase indulgence, and
reveals (R)-9b as a ‘mitocan’ that compromises the unique metabolic needs of cancer cells.
Castration resistant prostate cancer (CRPC) remains an incurable malignancy with limited treatment options and
is a significant cause of deaths in men worldwide (15). Limited efficacy and rapid development of resistance for
Enzalutamide and Abiraterone, AR antagonist treatment have established a new paradigm-to achieve realistic
remission, other cancer specific pathways, including metabolic must be compromised. This proposal is directed
towards detailed characterization of mitochondrial metabolism modulatory properties of ACK1/ATP5F1a
signaling and examine ability of (R)-9b to overcome Enzalutamide and abiraterone-resistant CRPCs. The
specific aims are as follows:
Specific Aim 1. Examine the mechanism by which ATP5F1a-phosphorylation regulates its activity in prostate
cancer
Specific Aim 2. Explore the role of ACK1/ATP5F1a signaling in prostate cancer models
Specific Aim 3. Detail in vivo characterization of ACK1/ATP5F1a signaling in enzalutamide and abiraterone-
resistance in mouse models of prostate cancer and patient derived xenografts (PDXs)

## Key facts

- **NIH application ID:** 10817081
- **Project number:** 5R01CA273054-02
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Nupam P Mahajan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $439,433
- **Award type:** 5
- **Project period:** 2023-04-01 → 2028-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10817081

## Citation

> US National Institutes of Health, RePORTER application 10817081, Regulation of Mitochondrial Metabolism by Tyr-phosphorylated ATP Synthase Alpha-Subunit and its Therapeutic Implications in Prostate Cancer (5R01CA273054-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10817081. Licensed CC0.

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