Related Experiment Video

Updated: Aug 4, 2026

Methods to Study Mrp4-containing Macromolecular Complexes in the Regulation of Fibroblast Migration
10:43

Methods to Study Mrp4-containing Macromolecular Complexes in the Regulation of Fibroblast Migration

Published on: May 19, 2016

Phospholipase A2-activating peptide-induced contraction of smooth muscle is mediated by protein kinase C--MAP kinase

H Yamada1, K N Bitar

  • 1Department of Pediatrics, University of Michigan Medical School, Ann Arbor 48109-0658, USA.

Biochemical and Biophysical Research Communications
|December 5, 1995
PubMed

Insights

Mammalian phospholipase A2-activating protein (PLAP) triggers smooth muscle contraction and MAP kinase activation. This effect is mediated by protein kinase C (PKC) and suggests a novel G protein-coupled pathway in smooth muscle.

Area of Science:

  • Cellular Biology
  • Physiology
  • Biochemistry

Background:

  • Mammalian phospholipase A2-activating protein (PLAP) is involved in cellular signaling pathways.
  • Smooth muscle contraction is a complex process regulated by various intracellular cascades.
  • Understanding the molecular mechanisms underlying smooth muscle function is crucial for treating related disorders.

Purpose of the Study:

  • To investigate the role of PLAP in smooth muscle cell contraction.
  • To elucidate the signaling pathways involved in PLAP-mediated smooth muscle responses.
  • To explore the potential involvement of protein kinase C (PKC) and MAP kinase in this process.

Main Methods:

  • Isolated rabbit rectosigmoid smooth muscle cells were used.
  • PLAP-induced contraction was measured.
  • MAP kinase activity was assessed using myelin basic protein (MBP) as a substrate.
  • Inhibitors of phospholipase A2 (PLA2) and PKC were employed.

Main Results:

  • PLAP induced rapid and sustained contraction of smooth muscle cells.
  • PLAP activated MAP kinase, with increased activity observed at 30 seconds and sustained at 4 minutes.
  • Inhibition of PLA2 or PKC abolished PLAP-induced contraction and MAP kinase activation.

Conclusions:

  • PLAP-induced smooth muscle contraction is mediated by the activation of a PKC-MAP kinase cascade.
  • This study suggests a potential role for PLA2-coupled G protein activation of the PKC-MAP kinase pathway in smooth muscle contraction.
  • PLAP represents a significant signaling molecule in smooth muscle physiology.

More Related Videos

Isolation of Intrapulmonary Artery and Smooth Muscle Cells to Investigate Vascular Responses07:56

Isolation of Intrapulmonary Artery and Smooth Muscle Cells to Investigate Vascular Responses

Published on: June 8, 2022

A Liposome Membrane Permeability Assay for Investigating the Effects of Phosphatidylinositol Phosphate Groups on Membranotropic Action of Venom PLA210:31

A Liposome Membrane Permeability Assay for Investigating the Effects of Phosphatidylinositol Phosphate Groups on Membranotropic Action of Venom PLA2

Published on: September 26, 2025

Related Concept Videos

What are Second Messengers?01:12

What are Second Messengers?

Because many receptor binding ligands are hydrophilic, they do not cross the cell membrane and thus their message must be relayed to a second messenger on the inside. There are several second messenger pathways, each with their own way of relaying information. G-protein coupled receptors can activate both phosphoinositol and cyclic AMP (cAMP) second messenger pathways. The phosphoinositol path is active when the receptor induces phospholipase C to hydrolyze the phospholipid,...
Amplifying Signals via Second Messengers01:15

Amplifying Signals via Second Messengers

Many receptor binding ligands are hydrophilic; they do not cross the cell membrane but bind to cell-surface receptors. Thus, their message must be relayed by second messengers present in the cell cytoplasm. There are several second messenger pathways, each with its own way of relaying information. For example, the G protein-coupled receptors can activate both phosphoinositol and cyclic AMP (cAMP) second messenger pathways. The phosphoinositol pathway is active when the receptor induces...
cAMP-dependent Protein Kinase Pathways01:25

cAMP-dependent Protein Kinase Pathways

Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
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...
Calmodulin-dependent Signaling01:16

Calmodulin-dependent Signaling

Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Nitric Oxide Signaling Pathway01:28

Nitric Oxide Signaling Pathway

Nitric oxide (NO), an inorganic gas, acts as a potent second messenger in most animal and plant tissues. NO diffuses out of the cells that produce it and enters the neighboring cells to generate a downstream response. NO synthase (NOS) catalyzes NO production by the deamination of the amino acid arginine. There are three isoforms of NOS. Endothelial cells have endothelial NOS (eNOS), nerve and muscle cells have neuronal NOS (nNOS), and macrophages produce inducible NOS (iNOS) upon exposure to...