Related Experiment Video
Updated: Jul 15, 2025
06:56
Author Spotlight: Developing Tools to Tune the Activity of Tyrosine Phosphatases
Published on: September 6, 2024
408
Structural and dynamic changes in P-Rex1 upon activation by PIP3 and inhibition by IP4
Sandeep K Ravala1, Sendi Rafael Adame-Garcia2, Sheng Li3
1Departments of Biological Sciences and of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, United States.
Biorxiv : the Preprint Server for Biology
|September 25, 2023
Summary
Inositol tetraphosphate (IP4) inhibits P-Rex1 activity by stabilizing an autoinhibited conformation. This discovery reveals a novel regulatory mechanism for P-Rex1, crucial for neutrophil function and cancer metastasis.
Area of Science:
- Biochemistry
- Cell Biology
- Structural Biology
Background:
- P-Rex1 is a guanine-nucleotide exchange factor (GEF) vital for neutrophil chemotaxis and cancer metastasis.
- P-Rex1 is activated by PIP3 and Gβγ subunits, but its precise regulation is not fully understood.
Conclusions:
- IP4 acts as a negative regulator of P-Rex1, contributing to basal inhibition in neutrophils.
- The P-Rex1·IP4 structure represents a key autoinhibited state, providing insights into GEF regulation.
- Understanding P-Rex1 inhibition is critical for targeting neutrophil function in inflammation and cancer.
More Related Videos
Related Concept Videos
01:42Phosphoinositides and PIPs
8.6K
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...
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
8.6K
01:11IP3/DAG Signaling Pathway
12.2K
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...
12.2K
01:20The JAK-STAT Signaling Pathway
9.0K
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...
9.0K
01:31Regulation of the Unfolded Protein Response
2.5K
Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...
2.5K
01:22PI3K/mTOR/AKT Signaling Pathway
3.6K
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...
3.6K
01:19Interactions Between Signaling Pathways
6.3K
Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
6.3K