Alisa Glukhova-Projects

Alisa Glukhova-Projects

Researcher: 
Dr Alisa Glukhova

Projects

Last modified: 
Wed, 26/08/2020 - 4:49pm

Structural biology of the acyltransferase Porcupine

Porcupine (PORCN) is a transmembrane protein responsible for palmitoylation of all Wnts. There are four PORCN isoforms with different tissue distribution and activity profiles. The inhibition of PORCN results in abolishing of all Wnt signalling by suppressing Wnt secretion, leading to exploration of PORCN inhibitors for the treatment of multiple cancers.

This project focuses on the structural biology of PORCN, its recognition by Wnts and understanding how existing small molecules target PORCN.

Specifically, we are trying to determine the structure of PORCN, understand the structural basis for PORCN isoform selectivity and the structure-activity relationships of small molecules in current clinical trials.

Understanding the Wnt signalling through G proteins

The Wnt signalling is initiated by Wnt interactions with their receptors, Frizzled (FZD), and co-receptors. Different combinations of Wnt/FZD/co-receptors initiate different signalling cascades. At least some cascades stem from FZD coupling and activation of the G proteins following FZD-Wnt interactions.

There is currently no structure of the full-length FZD receptors and the mechanisms of their activation by Wnts are unknown. More importantly, evidence suggests that different Wnts can lead to FZD coupling to different G proteins.

This project focuses on understanding the structure of FZD receptors, mechanisms of their activation by Wnts, and the selectivity of FZD-Wnt interaction.

Structural basing for Wnt acylation

Wnt proteins are essential for many cell processes, including differentiation and migration. Porcupine (PORCN) is a transmembrane protein that modifies all Wnts with a fatty molecule, which is crucial for Wnt secretion and activity. Because of this, PORCN inhibitors show potential for treating various types of human cancers. Using cryo-EM, we can achieve the highest resolution PORCN structure (2.5 Å) with a small molecule inhibitor. This student project will expand upon our PORCN work and employ cryo-EM to determine the PORCN-Wnt complex structure, aiming to understand Wnt modification by PORCN at the molecular level.