Our laboratory aims to understand the molecular details of cell signalling pathways involved in cell development, fate determination, and polarity. These processes are important in embryonic development and maintenance of healthy tissues in adults. Because of this, their dysregulation underlies the cause of many human cancers.
Specifically, we are interested in understanding the molecular details of different steps in Wnt pathways. Wnt signalling is initiated by Wnts that bind to their receptors and co-receptors, leading to different cellular responses. Multiple steps of the Wnt pathways have been explored as therapeutic targets for cancer treatment, however, due to the extreme complexity and importance of Wnt signalling for normal tissue homeostasis, its safe and selective targeting remains a challenge.
We are combining cryo-electron microscopy and x-ray crystallography with biochemical, biophysical, and pharmacological assays to gain insights into the atomic-level details of individual proteins as well as large complexes involved in Wnt signal transduction. Such detailed understanding is crucial for the development of novel therapeutics and improving ones that are already in clinical trials.
Our mission is to facilitate drug discovery by leveraging structural biology to better understand the structure and function of signaling proteins.
Since its establishment in 2020, our laboratory has determined the highest resolution structure of the key Wnt-lipidating enzyme, Porcupine (manuscript in preparation), as well as the first structure of the lipid-modifying enzyme 12-lipoxygenase (manuscript under review) by cryo-EM.
Through collaborations with other laboratories at WEHI we have contributed to understanding how Sars-CoV-2 spike protein is neutralised by biologics (PMID 36213007, 34610292 and 33893175), the activation mechanism of PINK-1 (PMID 34933320). Our collaborations with Monash institute of Pharmaceutical Sciences contributed to understanding of ligand binding at the G protein coupled receptors and ion channels (multiple manuscripts under review and in preparation).
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 achieved 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.
Wnt proteins play a vital role in various cell processes, including differentiation and migration. As lipophilic molecules, Wnts require carrier proteins to maintain solubility outside cells. The exact interaction mechanism between Wnts and these carrier proteins remains unknown. Additionally, other extracellular proteins regulate Wnt signaling through interactions and modifications of Wnt proteins. Understanding these processes and their regulation will ultimately help discover new therapeutic targets.
This project will employ cryo-electron microscopy, x-ray crystallography, and complementary techniques to investigate Wnt complexes with extracellular proteins, such as afamin, serum albumin, and Norrin, to enhance understanding of their interactions and regulatory functions.
Wnt signaling is initiated by Wnt proteins when they interact with their receptors, Frizzled, and co-receptors. Although this step is crucial for understanding Wnt signaling biology and developing new therapies, the molecular details remain elusive. Existing structural information on individual steps is incomplete, and the full picture is yet to be uncovered. This ambitious project aims to employ structural biology and complementary techniques to gain insights into how Wnt binding leads to Frizzled activation and signal transmission into the cell.
The enzyme 12-Lipoxygenase (12-LOX) is a promising drug target for preventing platelet activation and thrombosis. ML355, a 12-LOX inhibitor, has shown potential in treating heparin-induced thrombocytopenia. In collaboration with Thal, Holman, and Holinstat laboratories, we were the first to determine the high-resolution structures of human 12-LOX, including structures with the clinically relevant inhibitor ML355 and an endogenous acyl-coenzyme A. This project aims to build upon our structural studies to further understand 12-LOX biology, including its oligomeric states, catalysis, and membrane binding, and to gain insights into a new generation of 12-LOX inhibitors.
Our team collaborates with other labs at WEHI (Tham, Kommander and Kershaw labs), at Monash Institute for Pharmaceutical sciences (Thal lab), Karolinska Institutet (Schulte lab), University of California Santa Cruz (Holman lab) and University of Michigan (Holinstat lab).