c-Cbl and Cbl-b ubiquitin ligases: substrate diversity and the negative regulation of signalling responses
Related Experiment Video
Updated: Aug 15, 2026
Evaluation of Substrate Ubiquitylation by E3 Ubiquitin-ligase in Mammalian Cell Lysates
Published on: May 10, 2022
Christine B F Thien1, Wallace Y Langdon
1School of Surgery and Pathology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia. Christine.Thien@uwa.edu.au
Abstract:
The activation of signalling pathways by ligand engagement with transmembrane receptors is responsible for determining many aspects of cellular function and fate. While these outcomes are initially determined by the nature of the ligand and its receptor, it is also essential that intracellular enzymes, adaptor proteins and transcription factors are correctly assembled to convey the intended response. In recent years, it has become evident that proteins that regulate the amplitude and duration of these signalling responses are also critical in determining the function and fate of cells. Of these, the Cbl family of E3 ubiquitin ligases and adaptor proteins has emerged as key negative regulators of signals from many types of cell-surface receptors. The array of receptors and downstream signalling proteins that are regulated by Cbl proteins is diverse; however, in most cases, the receptors have a common link in that they either possess a tyrosine kinase domain or they form associations with cytoplasmic PTKs (protein tyrosine kinases). Thus Cbl proteins become involved in signalling responses at a time when PTKs are first activated and therefore provide an initial line of defence to ensure that signalling responses proceed at the desired intensity and duration.
Insights
The Cbl family of E3 ubiquitin ligases acts as crucial negative regulators in cellular signaling pathways. These proteins control signal intensity and duration, ensuring proper cell function and fate determination by modulating receptor tyrosine kinases.
Area of Science:
- Cellular Biology
- Molecular Biology
- Biochemistry
Background:
- Cellular function and fate are determined by signaling pathways activated by ligand-receptor interactions.
- Intracellular protein assembly is crucial for signal transduction.
- Proteins regulating signal amplitude and duration critically influence cellular outcomes.
Purpose of the Study:
- To highlight the role of the Cbl family of E3 ubiquitin ligases as key negative regulators of cell-surface receptor signaling.
- To explain how Cbl proteins modulate the intensity and duration of signaling responses.
Main Methods:
- The abstract does not specify methods, but implies analysis of protein interactions and signaling pathways.
- Focus on the regulatory mechanisms of Cbl proteins in tyrosine kinase-associated signaling.
Main Results:
- Cbl proteins are identified as essential negative regulators of diverse cell-surface receptor signals.
- Cbl proteins primarily target receptors with tyrosine kinase domains or those associated with protein tyrosine kinases (PTKs).
- Cbl proteins act early in signaling cascades, controlling signal intensity and duration.
Conclusions:
- The Cbl family of E3 ubiquitin ligases plays a vital role in maintaining cellular homeostasis by negatively regulating signaling pathways.
- Proper regulation of signaling by Cbl proteins is essential for determining cell function and fate.
- Cbl proteins provide a critical defense mechanism against excessive signaling from tyrosine kinase receptors.
Related Concept Videos
02:04Covalently Linked Protein Regulators
These groups modify specific amino acids in a protein.
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...
01:22Amplifying Signals via Enzymatic Cascade
01:19Interactions Between Signaling Pathways
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
01:57Protein Complexes with Interchangeable Parts
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
01:30Assembly of Signaling Complexes
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...