Cholesterol inhibits oncogenic EphA2 activation

Schuck, R.; Ward, A.; Sahoo, A. R.; Rybak, J.; Pyron, R.; Trybala, T.; Simmons, T.; Baccile, J.; Sgouralis, I.; Buck, M.; Lamichhane, R.; Barrera, F. N.

doi:10.1101/2024.06.10.598255

bioRxiv · 10.1101/2024.06.10.598255

Cholesterol inhibits oncogenic EphA2 activation

Schuck, R.·Ward, A.·Sahoo, A. R.·Rybak, J.·Pyron, R.·Trybala, T.·Simmons, T.·Baccile, J.·Sgouralis, I.·Buck, M.·Lamichhane, R.·Barrera, F. N.

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Abstract

The receptor tyrosine kinase EphA2 drives cancer malignancy by facilitating metastasis. EphA2 can be found in different self-assembly states: as a monomer, dimer, and oligomer. However, our understanding remains limited regarding which EphA2 state is responsible for driving pro-metastatic signaling. To address this limitation, we have developed SiMPull-POP, a single-molecule method for accurate quantification of membrane protein self-assembly. Our experiments revealed that a reduction of plasma membrane cholesterol strongly promoted EphA2 self-assembly. Indeed, low cholesterol caused a similar effect to the EphA2 ligand ephrinA1-Fc. These results indicate that cholesterol inhibits EphA2 assembly. Phosphorylation studies in different cell lines revealed that low cholesterol increased phospho-serine levels, the signature of oncogenic signaling. Investigation of the mechanism that cholesterol uses to inhibit the assembly and activity of EphA2 indicate an in-trans effect, where EphA2 is phosphorylated by protein kinase A downstream of beta-adrenergic receptor activity, which cholesterol also inhibits. Our study not only provides new mechanistic insights on EphA2 oncogenic function, but also suggests that cholesterol acts as a molecular safeguard mechanism that prevents uncontrolled self-assembly and activation of EphA2.

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Schuck, R., Ward, A., Sahoo, A. R., Rybak, J., Pyron, R., Trybala, T., Simmons, T., Baccile, J., Sgouralis, I., Buck, M., Lamichhane, R., Barrera, F. N.. 2024-06-10. Cholesterol inhibits oncogenic EphA2 activation. https://doi.org/10.1101/2024.06.10.598255

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