Related Experiment Video

Updated: Aug 17, 2026

Co-immunoprecipitation Assay for Studying Functional Interactions Between Receptors and Enzymes
09:40

Co-immunoprecipitation Assay for Studying Functional Interactions Between Receptors and Enzymes

Published on: September 28, 2018

p125FAK tyrosine phosphorylation and focal adhesion assembly: studies with phosphotyrosine phosphatase inhibitors

P Defilippi1, S F Retta, C Olivo

  • 1Dipartimento di Genetica, Biologia e Chimica Medica, Universita di Torino, Italy.

Experimental Cell Research
|November 1, 1995
PubMed

Insights

Phosphotyrosine phosphatases (PTPases) regulate focal adhesion kinase (p125FAK) phosphorylation. Actin cytoskeleton assembly inhibits PTPases, maintaining p125FAK phosphorylation and focal adhesions.

Area of Science:

  • Cell Biology
  • Biochemistry
  • Molecular Biology

Background:

  • p125FAK is a key tyrosine kinase in integrin signaling.
  • Phosphotyrosine phosphatases (PTPases) dephosphorylate p125FAK.
  • Modulating PTPase activity can alter p125FAK phosphorylation.

Purpose of the Study:

  • To investigate the role of PTPases in regulating p125FAK phosphorylation.
  • To examine the relationship between p125FAK phosphorylation, focal adhesions, and the actin cytoskeleton.

Main Methods:

  • Utilized vanadate and phenylarsine oxide (PAO) as PTPase inhibitors.
  • Analyzed protein tyrosine phosphorylation levels via Western blotting.
  • Assessed focal adhesion and actin stress fiber assembly using immunofluorescence microscopy.
  • Investigated the effects of cytochalasin D (CD) on the cytoskeleton and p125FAK phosphorylation.

Main Results:

  • Vanadate and PAO increased p125FAK tyrosine phosphorylation in a dose-dependent manner.
  • PAO primarily affected a 120-140 kDa protein band, while vanadate showed a biphasic effect.
  • Increased p125FAK phosphorylation correlated with enhanced focal adhesion and actin stress fiber formation.
  • Cytochalasin D disrupted actin cytoskeleton and reduced p125FAK phosphorylation.
  • Co-treatment with PTPase inhibitors and CD preserved focal adhesions and p125FAK phosphorylation.

Conclusions:

  • Actin cytoskeleton assembly plays a role in inhibiting PTPases that target p125FAK.
  • PTPase activity is crucial for regulating p125FAK phosphorylation and downstream signaling.
  • The interplay between the actin cytoskeleton and PTPases influences cell adhesion dynamics.

More Related Videos

Assessing Cellular Target Engagement by SHP2 (PTPN11) Phosphatase Inhibitors08:45

Assessing Cellular Target Engagement by SHP2 (PTPN11) Phosphatase Inhibitors

Published on: July 17, 2020

Development and Application of Rapamycin-regulated Tyrosine Phosphatases06:56

Development and Application of Rapamycin-regulated Tyrosine Phosphatases

Published on: September 6, 2024

Related Concept Videos

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...
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 the...
Receptor Tyrosine Kinases01:26

Receptor Tyrosine Kinases

Receptor tyrosine kinases or RTKs are membrane-bound receptors that phosphorylate specific tyrosine on protein substrates. RTKs regulate cellular growth, differentiation, survival, and migration. They contain an extracellular ligand binding domain, a transmembrane domain, and a cytosolic tail with intrinsic kinase activity. Several extracellular signaling molecules activate RTKs in one or more ways and relay the signal downstream. Ligands such as platelet-derived growth factor (PDGF) or...
The JAK-STAT Signaling Pathway01:20

The JAK-STAT Signaling Pathway

Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as  SH2...
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 rapamycin-insensitive companion...
Intracellular Signaling Affects Focal Adhesions01:17

Intracellular Signaling Affects Focal Adhesions

Integrins act both as extracellular input receivers and as intracellular processing activators. As their name suggests, integrins are entirely integrated into the membrane structure. Their hydrophobic membrane-spanning regions interact with the phospholipid bilayer's hydrophobic region. These membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors. They activate intracellular response cascades when their effectors are bound and active.
Some...