Related Experiment Video

Updated: Jul 4, 2026

A TIRF Microscopy Technique for Real-time, Simultaneous Imaging of the TCR and its Associated Signaling Proteins
16:10

A TIRF Microscopy Technique for Real-time, Simultaneous Imaging of the TCR and its Associated Signaling Proteins

Published on: March 22, 2012

PCTA: a new player in TGF-beta signaling

Fang Liu1

  • 1Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, 679 Hoes Lane, Piscataway, NJ 08854, USA. fangliu@cabm.rutgers.edu

Science Signaling
|November 20, 2008
PubMed

Insights

PCTA promotes TGF-beta signaling by competing with TGIF, freeing cytoplasmic PML. This interaction enhances Smad2/3 phosphorylation, driving TGF-beta-mediated growth inhibition and transcriptional regulation.

Area of Science:

  • Cellular Biology
  • Molecular Signaling
  • Biochemistry

Background:

  • Transforming growth factor beta (TGF-beta) is a crucial regulator of cellular functions.
  • Canonical TGF-beta signaling involves Smad proteins, transducing signals from cell surface receptors to the nucleus.
  • Smad2 and Smad3 phosphorylation by TGF-beta receptors is a key early step.

Purpose of the Study:

  • To elucidate the role of PCTA (PML competitor for TGIF association) in TGF-beta signaling.
  • To investigate how PCTA influences the interaction of cytoplasmic promyelocytic leukemia protein (cPML) with TGIF and Smad proteins.
  • To determine the impact of PCTA on TGF-beta-mediated transcriptional regulation and cellular responses.

Main Methods:

  • Investigated protein-protein interactions using biochemical assays.
  • Studied the localization of key signaling proteins (cPML, TGIF) within cells.
  • Assessed the effect of PCTA on Smad2/3 phosphorylation.
  • Analyzed TGF-beta-mediated transcriptional activity and growth inhibition.

Main Results:

  • PCTA competes with cPML for binding to TGIF, a negative regulator of TGF-beta signaling.
  • This competition leads to the accumulation of cPML in the cytoplasm.
  • Cytoplasmic cPML facilitates the interaction between Smad2/3 and SARA, promoting Smad phosphorylation.
  • PCTA enhances TGF-beta-mediated transcriptional regulation and growth inhibition.

Conclusions:

  • PCTA acts as a novel positive regulator of TGF-beta signaling.
  • PCTA promotes TGF-beta pathway activation by modulating the cPML-TGIF interaction.
  • PCTA's mechanism involves enhancing Smad2/3 phosphorylation and downstream transcriptional events.

More Related Videos

Studying TGF-β Signaling and TGF-β-induced Epithelial-to-mesenchymal Transition in Breast Cancer and Normal Cells06:54

Studying TGF-β Signaling and TGF-β-induced Epithelial-to-mesenchymal Transition in Breast Cancer and Normal Cells

Published on: October 27, 2020

Tension Gauge Tether Probes for Quantifying Growth Factor Mediated Integrin Mechanics and Adhesion09:56

Tension Gauge Tether Probes for Quantifying Growth Factor Mediated Integrin Mechanics and Adhesion

Published on: February 11, 2022

Related Concept Videos

GTPases and their Regulation02:14

GTPases and their Regulation

Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒  small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins,...
9.6K
Assembly of Signaling Complexes01:30

Assembly of Signaling Complexes

Multiprotein signaling complexes are formed in a dynamic process involving protein-protein interactions at the cytoplasmic domain of transmembrane receptors or enzymatic and non-enzymatic proteins associated with the receptor. These complexes ensure the activation and propagation of intracellular signals that regulate cell functions.
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
6.4K
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...
16.7K
Small GTPases - Ras and Rho01:24

Small GTPases - Ras and Rho

Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
5.0K
TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors...
10.1K
Activation and Inactivation of G Proteins01:22

Activation and Inactivation of G Proteins

Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high...
10.3K