Related Experiment Video

Updated: Aug 1, 2026

Genome-wide Protein-protein Interaction Screening by Protein-fragment Complementation Assay (PCA) in Living Cells
08:38

Genome-wide Protein-protein Interaction Screening by Protein-fragment Complementation Assay (PCA) in Living Cells

Published on: March 3, 2015

Structural delineation of the calcineurin-NFAT interaction and its parallels to PP1 targeting interactions

Huiming Li1, Anjana Rao, Patrick G Hogan

  • 1Department of Pathology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.

Journal of Molecular Biology
|September 15, 2004
PubMed

Insights

Calcineurin, a key enzyme in calcium signaling, interacts with nuclear factor of activated T cells (NFAT) via a specific motif. This study reveals the structural basis of this interaction, offering insights into phosphatase evolution.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cell Signaling

Background:

  • Calcineurin is a crucial phosphoprotein phosphatase mediating intracellular calcium (Ca2+) signals.
  • It interacts with substrates like nuclear factor of activated T cells (NFAT) and regulatory proteins (e.g., AKAP79, Cabin1).
  • The PxIxIT motif is essential for calcineurin-NFAT binding.

Purpose of the Study:

  • To elucidate the structural underpinnings of calcineurin's interaction with NFAT.
  • To define the structural basis for calcineurin binding to other proteins containing the PxIxIT motif.
  • To compare the calcineurin-PxIxIT interaction with related phosphatase interactions.

Main Methods:

  • Structural biology techniques (likely X-ray crystallography or cryo-EM) were used to determine the complex structures.
  • Biochemical assays may have been employed to validate binding interactions.
  • Comparative analysis with known phosphatase structures was performed.

Main Results:

  • The precise structural details of the calcineurin-NFAT complex were defined.
  • The interaction interface for the PxIxIT motif in other calcineurin-binding proteins was characterized.
  • A structural homology was identified between the calcineurin-PxIxIT interaction and that of protein phosphatase 1.

Conclusions:

  • The study provides a detailed structural map of calcineurin's substrate and regulatory protein interactions.
  • The findings highlight the conserved nature of the PxIxIT binding mechanism across different phosphatases.
  • This research suggests evolutionary remodeling of an ancestral docking site in related phosphatases.

More Related Videos

Visualization of Protein-protein Interaction in Nuclear and Cytoplasmic Fractions by Co-immunoprecipitation and In Situ Proximity Ligation Assay10:05

Visualization of Protein-protein Interaction in Nuclear and Cytoplasmic Fractions by Co-immunoprecipitation and In Situ Proximity Ligation Assay

Published on: January 16, 2017

A Chromatin Immunoprecipitation Assay to Identify Novel NFAT2 Target Genes in Chronic Lymphocytic Leukemia09:52

A Chromatin Immunoprecipitation Assay to Identify Novel NFAT2 Target Genes in Chronic Lymphocytic Leukemia

Published on: December 4, 2018

Related Concept Videos

Protein-protein Interfaces02:04

Protein-protein Interfaces

Many proteins form complexes to carry out their functions, making protein-protein interactions (PPIs) essential for an organism's survival. Most PPIs are stabilized by numerous weak noncovalent chemical forces. The physical shape of the interfaces determines the way two proteins interact. Many globular proteins have closely-matching shapes on their surfaces, which form a large number of weak bonds. Additionally, many PPIs occur between two helices or between a surface cleft and a polypeptide...
Regulation of Nuclear Protein Sorting01:45

Regulation of Nuclear Protein Sorting

Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...
NF-κB-dependent Signaling Pathway02:26

NF-κB-dependent Signaling Pathway

The transcription factor NF-κB was discovered in 1986 in the lab of Nobel laureate Professor David Baltimore, for its interaction with the immunoglobulin light chain enhancer in B-cells. After more than three decades of study, it is now evident that NF-κB regulates the expression of over 100 genes. Most of these genes play an essential role in the innate and adaptive immune responses as well as the inflammatory responses of animals.
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...
Non-Canonical Wnt Signaling Pathways01:41

Non-Canonical Wnt Signaling Pathways

Wnt is a zygotic effect gene that is expressed during very early embryonic development. It regulates various processes in animals starting from early development through the adult stage, such as organogenesis in the embryo and maintenance of neuronal and blood stem cells. Wnt proteins can induce a wide variety of intracellular pathways depending upon the specific abilities of different Wnt ligands to form a complex with shared and cognate receptors in the presence of different co-receptors. The...