Transmembrane Inhibitor of RICTOR/mTORC2 in Hematopoietic Progenitors

Area of Science:

• Cellular biology
• Molecular oncology
• Hematopoiesis

Background:

• The serine/threonine kinase mTOR is crucial for cellular processes and is often activated in human cancers.
• mTOR exists in complexes mTORC1 and mTORC2, with mTORC2's regulation being poorly understood.
• Hematopoietic progenitor cells play a key role in blood cell development and immune responses.

Purpose of the Study:

• To identify novel regulators of mTORC2 activity in hematopoietic progenitor cells.
• To investigate the role of a newly discovered transmembrane molecule in mTORC2 regulation.
• To explore the therapeutic potential of targeting mTORC2 in T cell acute lymphoid leukemia (T-ALL).

Main Methods:

• Identification and characterization of a transmembrane molecule interacting with RICTOR, an mTORC2 component.
• Assessing the impact of the molecule (UT2) on mTORC2 enzymatic activity and downstream signaling pathways.
• Evaluating the effect of modulating UT2 levels on animal survival in a T-ALL model.

Main Results:

• A transmembrane molecule, UT2, was identified that physically interacts with and inhibits RICTOR, a key component of mTORC2.
• UT2 negatively regulates mTORC2 activity, leading to reduced phosphorylation of AKT(S473), PKCα, and NDRG1.
• Increased FOXO transcriptional activity was observed in an mTORC2-dependent manner.
• Modulating UT2 levels significantly altered animal survival in an mTORC2-sensitive T-ALL model.

Conclusions:

• UT2 is an upstream inhibitor of mTORC2 in hematopoietic cells, impacting critical cellular signaling pathways.
• Targeting UT2 presents a potential therapeutic strategy to reduce mortality in NOTCH-induced T-ALL.
• This transmembrane inhibitor of mTORC2 offers a novel target for modulating this vital cell regulatory pathway.