Related Experiment Video

Updated: Jul 14, 2026

Identification of Kinase-substrate Pairs Using High Throughput Screening
11:13

Identification of Kinase-substrate Pairs Using High Throughput Screening

Published on: August 29, 2015

Stimulus-dependent myristoylation of a major substrate for protein kinase C

A A Aderem1, K A Albert, M M Keum

  • 1Rockefeller University, New York, New York 10021.

Nature
|March 24, 1988
PubMed

Insights

Bacterial lipopolysaccharide (LPS) triggers macrophage responses by myristoylating a protein kinase C (PKC) substrate. This myristoylation may target the protein to the cell membrane, mediating LPS-induced cellular signaling.

Area of Science:

  • Immunology
  • Cell Biology
  • Biochemistry

Background:

  • Bacterial lipopolysaccharide (LPS) is a key gram-negative bacteria component that activates immune cells like macrophages.
  • LPS profoundly impacts macrophage function, enhancing protein and metabolite release, but the underlying molecular mechanisms remain unclear.
  • Previous studies identified LPS-induced myristoylation of macrophage proteins, including a 68K protein.

Purpose of the Study:

  • To investigate the molecular mechanisms by which LPS induces macrophage secretory responses.
  • To identify and characterize the 68K myristoylated protein found in macrophages.
  • To explore the role of protein myristoylation in LPS-mediated cellular signaling.

Main Methods:

  • Macrophage protein analysis using techniques to detect myristoylation.
  • Comparison of the 68K myristoylated protein with known cellular substrates.
  • Subcellular fractionation to determine protein localization.

Main Results:

  • The 68K myristoylated protein in macrophages is identified as similar or identical to the 80/87K protein, a known substrate for protein kinase C (PKC).
  • This myristoylated PKC substrate is found to be quantitatively associated with the cell membrane fraction.
  • LPS stimulation promotes the myristoylation of this specific PKC substrate in macrophages.

Conclusions:

  • Myristoylation of the 80/87K PKC substrate by LPS may serve as a critical step in targeting this protein to the macrophage membrane.
  • This membrane localization is proposed to be a key component of the signal transduction pathway for LPS-induced stimulus-response coupling.
  • Understanding this pathway offers insights into gram-negative bacterial immune interactions and macrophage activation.

More Related Videos

Oligopeptide Competition Assay for Phosphorylation Site Determination09:16

Oligopeptide Competition Assay for Phosphorylation Site Determination

Published on: May 18, 2017

Characterization at the Molecular Level using Robust Biochemical Approaches of a New Kinase Protein11:23

Characterization at the Molecular Level using Robust Biochemical Approaches of a New Kinase Protein

Published on: June 30, 2019

Related Concept Videos

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...
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...
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
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,...
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,...