Mechanism of c-Cbl Transition from Autoinhibited to Partially Open State via Substrate Binding

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Cellular Casitas B-lineage lymphoma (c-Cbl) is a RING-type E3 ligase regulating protein degradation.
• Dysregulation of c-Cbl is linked to solid tumors and hematological malignancies.
• Substrate binding induces a conformational change critical for c-Cbl activation and E3 ligase function.

Purpose of the Study:

• To elucidate the molecular mechanism of c-Cbl conformational transition upon substrate binding.
• To identify key intermediate states in the c-Cbl activation process.
• To provide insights for developing small molecules targeting c-Cbl.

Main Methods:

• Nudged elastic band (NEB) calculations.
• Molecular dynamics (MD) simulations.
• Markov state model (MSM) analysis.

Main Results:

• Revealed the molecular mechanism of c-Cbl transformation from autoinhibited to partially open states.
• Identified key metastable states during substrate-induced conformational changes.
• Characterized the opening of the RING domain and exposure of E2 recognition sites.

Conclusions:

• The study clarifies the conformational dynamics of c-Cbl activation.
• Identified critical intermediate states for targeted drug development.
• Findings facilitate the design of novel c-Cbl-targeting therapeutics for cancer treatment.