Insertion Depth Modulates Protein Kinase C-δ-C1b Domain Interactions with Membrane Cholesterol as Revealed by MD Simulations


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Date

2023-03

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

Protein kinase C delta (PKC-δ) is an important signaling molecule in human cells that has both proapoptotic as well as antiapoptotic functions. These conflicting activities can be modulated by two classes of ligands, phorbol esters and bryostatins. Phorbol esters are known tumor promoters, while bryostatins have anti-cancer properties. This is despite both ligands binding to the C1b domain of PKC-δ (δC1b) with a similar affinity. The molecular mechanism behind this discrepancy in cellular effects remains unknown. Here, we have used molecular dynamics simulations to investigate the structure and intermolecular interactions of these ligands bound to δC1b with heterogeneous membranes. We observed clear interactions between the δC1b-phorbol complex and membrane cholesterol, primarily through the backbone amide of L250 and through the K256 side-chain amine. In contrast, the δC1b-bryostatin complex did not exhibit interactions with cholesterol. Topological maps of the membrane insertion depth of the δC1b-ligand complexes suggest that insertion depth can modulate δC1b interactions with cholesterol. The lack of cholesterol interactions suggests that bryostatin-bound δC1b may not readily translocate to cholesterol-rich domains within the plasma membrane, which could significantly alter the substrate specificity of PKC-δ compared to δC1b-phorbol complexes.

Publication status

published

Editor

Book title

Volume

24 (5)

Pages / Article No.

4598

Publisher

MDPI

Event

Edition / version

Methods

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Date collected

Date created

Subject

protein kinase C; cholesterol; bryostatin; phorbol esters; molecular dynamics; membrane bilayer; lipid rafts

Organisational unit

09681 - Barnes, Alexander / Barnes, Alexander check_circle

Notes

Funding

201070 - Dynamic Nuclear Polarization at Room Temperature for High Sensitivity Nuclear Magnetic Resonance (SNF)

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