Related Experiment Video
Updated: May 21, 2025
High-Throughput Cellular Profiling of Targeted Protein Degradation Compounds Using HiBiT CRISPR Cell Lines
Published on: November 9, 2020
Razing the scaffolding: the elimination of non-catalytic functions of kinases through targeted protein degradation
Sarah Pogash1, Steven Fletcher1,2
1Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy 20 N. Pine St. Baltimore MD 21201 USA steven.fletcher@rx.umaryland.edu.
Abstract:
Overexpression and activation of kinases often results in cancer initiation and progression through both catalytic and non-catalytic functions that promote rapid proliferation, growth, survival, and metastasis of cells. Catalytic functions are effectively blocked with the use of ATP-competitive inhibitors, however drug-resistant mutations are emerging all the time. Further, single-agent ATP-competitive inhibitors sometimes fail to eliminate oncogenic properties of the targeted kinase, likely due to (non-targeted) non-catalytic functions that are maintained. Non-catalytic functions - such as scaffolding roles, where the kinase may interact with other proteins to coordinate cellular activities or protect them from degradation by the proteasome - may be targeted through the development of protein-protein interaction (PPI) inhibitors, although this is a highly challenging endeavour. To overcome the limitations of classical (ATP-competitive) inhibitors (and circumvent the formidable feat required in the development of PPI inhibitors), which operate through "occupancy-driven" pharmacology, targeted protein degradation, as showcased by proteolysis targeting chimeras (PROTACs), is fast becoming a highly sought-after goal for a large plethora of protein targets, and is governed by "event-driven" pharmacology. Because PROTACs result in the degradation of the protein of interest, these compounds are predicted to both catalytic and non-catalytic functions of a targeted kinase. Herein, we focus on the development of PROTACs that target (i) the scaffolding roles of focal adhesion kinase (FAK) that are associated with the formation of signaling units involved in migration and invasion events and (ii) the scaffolding roles of Aurora-A kinase (AURKA), which play a role in the protection of MYC proteins from proteasomal degradation.
Insights
Targeted protein degradation using proteolysis targeting chimeras (PROTACs) offers a novel approach to inhibit both catalytic and non-catalytic kinase functions. This strategy degrades target proteins, overcoming limitations of traditional inhibitors and addressing drug resistance in cancer.
Area of Science:
- Molecular Biology
- Oncology
- Drug Discovery
Background:
- Kinase overexpression drives cancer via catalytic and non-catalytic functions, promoting proliferation, survival, and metastasis.
- ATP-competitive inhibitors block catalytic kinase activity but face emerging drug resistance and fail to address non-catalytic functions.
- Non-catalytic roles, like scaffolding and protein stabilization, are crucial in cancer but challenging to target with traditional inhibitors.
Purpose of the Study:
- To explore targeted protein degradation via proteolysis targeting chimeras (PROTACs) as an alternative to classical kinase inhibitors.
- To develop PROTACs targeting the scaffolding functions of focal adhesion kinase (FAK) involved in cancer cell migration and invasion.
- To design PROTACs targeting the scaffolding functions of Aurora-A kinase (AURKA) in protecting MYC proteins from degradation.
Main Methods:
- Development of proteolysis targeting chimeras (PROTACs) for targeted protein degradation.
- Focus on inhibiting non-catalytic scaffolding functions of kinases, specifically FAK and AURKA.
- Utilizing event-driven pharmacology distinct from occupancy-driven classical inhibitors.
Main Results:
- PROTACs are predicted to degrade target proteins, thereby eliminating both catalytic and non-catalytic kinase functions.
- This approach circumvents limitations of ATP-competitive inhibitors, including drug resistance and incomplete target engagement.
- PROTACs offer a promising strategy to target kinase scaffolding roles implicated in cancer progression.
Conclusions:
- Targeted protein degradation via PROTACs represents a powerful 'event-driven' approach to cancer therapy.
- PROTACs can effectively degrade kinases, addressing both catalytic and non-catalytic oncogenic functions.
- This strategy holds potential for overcoming resistance mechanisms and targeting previously undruggable kinase functions.
Related Concept Videos
02:58Regulated Protein Degradation
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
02:54Protein Kinases and Phosphatases
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
01:13The Proteasome
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
01:22Amplifying Signals via Enzymatic Cascade
01:02Phosphorylation
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
01:22PI3K/mTOR/AKT Signaling Pathway