Related Experiment Video

Updated: Aug 10, 2026

Live-imaging of PKC Translocation in Sf9 Cells and in Aplysia Sensory Neurons
09:54

Live-imaging of PKC Translocation in Sf9 Cells and in Aplysia Sensory Neurons

Published on: April 6, 2011

A phospholipase A2-stimulating protein regulated by protein kinase C in Aplysia neurons

A Calignano1, D Piomelli, T C Sacktor

  • 1Howard Hughes Medical Institute, Center for Neurobiology and Behavior, Columbia University, New York, NY 10032.

Brain Research. Molecular Brain Research
|March 1, 1991
PubMed

Insights

Researchers identified a protein in Aplysia neurons that activates phospholipase A2 (PLA2). This protein

Area of Science:

  • Neuroscience
  • Biochemistry
  • Molecular Biology

Background:

  • Phospholipase A2 (PLA2) plays a crucial role in cellular signaling pathways.
  • Eicosanoid production is linked to various physiological and pathological processes.
  • Regulation of PLA2 activity in neuronal tissues is not fully understood.

Purpose of the Study:

  • To isolate and characterize a novel protein that stimulates PLA2 activity in neuronal tissue.
  • To investigate the role of this protein in eicosanoid release from neurons.
  • To explore the regulatory mechanisms, including phosphorylation, of this PLA2-stimulating protein.

Main Methods:

  • Partial purification of the protein from Aplysia nervous tissue using ion exchange chromatography and size-exclusion HPLC.
  • Extraction of the protein from membrane fractions using Tween 20.
  • Assay of PLA2-stimulating activity in intact Aplysia neurons labeled with [3H]arachidonic acid.
  • In vitro studies involving protein kinase C (PKC) and alkaline phosphatase treatments.

Main Results:

  • A 30,000 Mr thermolabile and trypsin-sensitive protein activating PLA2 was isolated from Aplysia nervous tissue.
  • A similar protein was detected in rat cerebral cortex.
  • The protein is loosely associated with membranes and can be extracted with Tween 20.
  • The protein promotes eicosanoid release from Aplysia neurons and is a substrate for PKC.
  • PLA2-stimulating activity is enhanced by phorbol dibutyrate (PDBu) and reduced by alkaline phosphatase treatment.

Conclusions:

  • A novel neuronal protein that regulates PLA2 activity has been identified.
  • Phosphorylation by PKC appears to be a key regulatory mechanism for this PLA2-stimulatory protein in neurons.
  • This finding provides insights into the regulation of eicosanoid signaling in the nervous system.

More Related Videos

Monitoring Changes in the Intracellular Calcium Concentration and Synaptic Efficacy in the Mollusc Aplysia09:51

Monitoring Changes in the Intracellular Calcium Concentration and Synaptic Efficacy in the Mollusc Aplysia

Published on: July 15, 2012

Isolation of Sensory Neurons of Aplysia californica for Patch Clamp Recordings of Glutamatergic Currents09:40

Isolation of Sensory Neurons of Aplysia californica for Patch Clamp Recordings of Glutamatergic Currents

Published on: July 10, 2013

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...
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...
Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
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,...