Related Experiment Video

Updated: May 18, 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

Phosphoinositide 5-phosphatases: How do they affect tumourigenesis?

Keiji Miyazawa1

  • 1Department of Biochemistry, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan. keiji-miyazawa@umin.ac.jp

Journal of Biochemistry
|September 28, 2012
PubMed

Insights

Phosphoinositide 5-phosphatases have unique characteristics influencing cell signaling. Understanding these lipid codes is crucial for deciphering complex cellular processes like proliferation and apoptosis.

Area of Science:

  • Biochemistry
  • Cell Biology
  • Molecular Signaling

Background:

  • Phosphorylation regulates biological molecule activity, often acting as a binary switch controlled by kinases and phosphatases.
  • Phosphoinositides (PtdIns) possess multiple phosphorylation sites, creating a complex 'lipid code' that dictates cellular functions.
  • Class I phosphoinositide 3-kinase (PI3K) generates PtdIns(3,4,5)P₃, a key signaling molecule involved in glucose uptake, cell proliferation, and apoptosis.

Purpose of the Study:

  • To investigate the unique characteristics of phosphoinositide 5-phosphatases.
  • To elucidate the role of phosphoinositide 5-phosphatases in cellular signaling pathways.
  • To understand how these enzymes contribute to the 'phosphoinositide code'.

Main Methods:

  • Analysis of phosphoinositide 5-phosphatase substrate specificities.
  • Investigating the enzymatic activity of phosphoinositide 5-phosphatases in vitro and in vivo.
  • Utilizing biochemical assays and cell-based models to study enzyme function.

Main Results:

  • Phosphoinositide 5-phosphatases exhibit distinct substrate specificities, contributing to the precise regulation of phosphoinositide levels.
  • These enzymes play a critical role in modulating signaling pathways downstream of PI3K.
  • The activity of phosphoinositide 5-phosphatases is not always inversely correlated with oncogenic potential, unlike some other phosphatases.

Conclusions:

  • Phosphoinositide 5-phosphatases are key regulators of the phosphoinositide code, with unique properties.
  • Their specific roles in cellular processes and disease warrant further investigation.
  • Understanding these enzymes offers potential therapeutic targets for diseases involving aberrant cell signaling.

More Related Videos

Radiolabeling and Quantification of Cellular Levels of Phosphoinositides by High Performance Liquid Chromatography-coupled Flow Scintillation10:52

Radiolabeling and Quantification of Cellular Levels of Phosphoinositides by High Performance Liquid Chromatography-coupled Flow Scintillation

Published on: January 6, 2016

Fluorescence-Based Measurements of Phosphatidylserine/Phosphatidylinositol 4-Phosphate Exchange Between Membranes08:49

Fluorescence-Based Measurements of Phosphatidylserine/Phosphatidylinositol 4-Phosphate Exchange Between Membranes

Published on: March 14, 2021

Related Concept Videos

Phosphoinositides and PIPs01:42

Phosphoinositides and PIPs

Phosphoinositides are a group of phospholipids containing a glycerol backbone with two fatty acid chains and a phosphate attached to a myoinositol sugar ring. The inositol head group extends into the cytoplasm, where it is modified by adding phosphate groups to form phosphatidylinositol phosphates or PIPs.
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
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...
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...
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...
IP3/DAG Signaling Pathway01:11

IP3/DAG Signaling Pathway

Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the  phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and produces two-second...
Abnormal Proliferation02:23

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...