Related Experiment Video

Updated: Sep 2, 2025

Oligopeptide Competition Assay for Phosphorylation Site Determination
09:16

Oligopeptide Competition Assay for Phosphorylation Site Determination

Published on: May 18, 2017

8.5K

Phosphorylation of OTUB1 at Tyr 26 stabilizes the mTORC1 component, Raptor

Seung Un Seo1, Seon Min Woo1, Min Wook Kim2

  • 1Department of Immunology, School of Medicine, Keimyung University, Daegu, 42601, South Korea.

Cell Death and Differentiation
|August 4, 2022
PubMed

Insights

The study reveals OTUB1 stabilizes Raptor, a key protein in mTORC1 signaling, through phosphorylation. Targeting OTUB1 phosphorylation could offer a new strategy against cancer drug resistance by down-regulating Raptor.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Oncology

Background:

  • Raptor is crucial for mTORC1 signaling and its high expression confers resistance to PI3K/mTOR inhibitors in cancer.
  • Understanding Raptor regulation is vital for developing effective cancer therapies.

Purpose of the Study:

  • To elucidate the mechanism by which OTUB1 stabilizes Raptor.
  • To investigate the role of OTUB1 phosphorylation in cancer cell response to anti-cancer drugs.

Main Methods:

  • Biochemical assays to determine the interaction between OTUB1 and Raptor.
  • Kinase assays to identify kinases phosphorylating OTUB1.
  • Analysis of phospho-OTUB1 and Raptor levels in patient samples.

Main Results:

  • OTUB1 stabilizes Raptor via a non-canonical mechanism involving tyrosine 26 (Y26) phosphorylation.
  • Non-receptor tyrosine kinases (Src, SRMS) phosphorylate OTUB1 at Y26, stabilizing Raptor.
  • Dephosphorylation of OTUB1 destabilizes Raptor, sensitizing cancer cells to drugs through mitochondrial dysfunction.
  • Elevated phospho-OTUB1 and Raptor levels were observed in renal clear cell carcinoma patients.

Conclusions:

  • OTUB1-mediated phosphorylation of Raptor is a novel regulatory pathway.
  • Targeting OTUB1 phosphorylation presents a potential therapeutic strategy for overcoming cancer drug resistance.
  • This pathway's dysregulation is implicated in renal clear cell carcinoma.

More Related Videos

Author Spotlight: Developing Tools to Tune the Activity of Tyrosine Phosphatases06:56

Author Spotlight: Developing Tools to Tune the Activity of Tyrosine Phosphatases

Published on: September 6, 2024

459
A RANKL-based Osteoclast Culture Assay of Mouse Bone Marrow to Investigate the Role of mTORC1 in Osteoclast Formation09:37

A RANKL-based Osteoclast Culture Assay of Mouse Bone Marrow to Investigate the Role of mTORC1 in Osteoclast Formation

Published on: March 15, 2018

13.3K

Related Concept Videos

PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a...
3.9K
mTOR Signaling and Cancer Progression03:03

mTOR Signaling and Cancer Progression

The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
3.9K
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
5.9K
Phosphorylation01:02

Phosphorylation

The addition or removal of phosphate groups from proteins is the most common chemical modification that regulates cellular processes. These modifications can affect the structure, activity, stability, and localization of proteins within cells as well as their interactions with other proteins.
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...
50.9K
Protein Kinases and Phosphatases02:54

Protein Kinases and Phosphatases

Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
13.3K
Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze...
8.7K