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Updated: May 11, 2026

Identification of Inositol Phosphate or Phosphoinositide Interacting Proteins by Affinity Chromatography Coupled to Western Blot or Mass Spectrometry
08:07

Identification of Inositol Phosphate or Phosphoinositide Interacting Proteins by Affinity Chromatography Coupled to Western Blot or Mass Spectrometry

Published on: July 26, 2019

Tespa1 is a novel inositol 1,4,5-trisphosphate receptor binding protein in T and B lymphocytes

Hiroshi Matsuzaki1, Takahiro Fujimoto, Takeharu Ota

  • 1Department of Cell Biology, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.

FEBS Open Bio
|May 8, 2013
PubMed

Insights

Tespa1, a key molecule in T-cell development, physically associates with inositol 1,4,5-trisphosphate receptors (IP3R) in immune cells. This interaction, crucial for immune function, is mediated by specific phenylalanine residues in Tespa1.

Area of Science:

  • Immunology
  • Molecular Biology
  • Cell Biology

Background:

  • Tespa1 is recognized as vital for T-cell development, but its specific molecular functions are not fully understood.
  • Inositol 1,4,5-trisphosphate receptors (IP3Rs) are critical regulators of intracellular calcium signaling.

Purpose of the Study:

  • To elucidate the molecular mechanisms underlying Tespa1's function in the immune system.
  • To investigate the interaction between Tespa1 and IP3R in lymphocytes.

Main Methods:

  • Sequence homology analysis comparing Tespa1 with known IP3R-binding proteins.
  • Co-immunoprecipitation assays to confirm physical association between Tespa1 and IP3R in T and B lymphocytes.
  • Site-directed mutagenesis to identify key residues involved in the Tespa1-IP3R interaction.

Main Results:

  • Tespa1 shares amino acid sequence homology with KRAP, an IP3R-binding protein.
  • Tespa1 physically interacts with IP3R in both T and B lymphocytes.
  • A specific pair of phenylalanine residues (Phe185/Phe186) in Tespa1 are essential for its binding to IP3R.

Conclusions:

  • Tespa1 functions in the immune system by associating with and potentially regulating IP3R.
  • The interaction between Tespa1 and IP3R is mediated by conserved phenylalanine residues, highlighting a conserved mechanism of IP3R regulation.
  • These findings provide novel insights into the molecular basis of Tespa1's role in immune cell function.
Keywords:
IP3RIP3R, Inositol 1,4,5-trisphosphate receptorKRAP, KRAS-induced actin-interacting protein.LymphocyteProtein–protein interactionSpleenTespa1Tespa1, thymocyte-expressed positive selection-associated 1Thymus

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