Related Experiment Video
Updated: Aug 5, 2026
08:05
Visualizing Membrane Ruffle Formation using Scanning Electron Microscopy
Published on: May 27, 2021
Phorbol esters stimulate macropinocytosis and solute flow through macrophages
1Department of Anatomy and Cellular Biology, Harvard Medical School, Boston, MA 02115.
Journal of Cell Science
|September 1, 1989
Summary
Phorbol myristate acetate (PMA) enhances pinocytosis in macrophages, increasing solute accumulation by promoting macropinosome formation and solute influx more than efflux.
Area of Science:
- Cell Biology
- Macrophage Biology
- Endocytosis Research
Background:
- Bone marrow-derived macrophages utilize pinocytosis for nutrient uptake and waste removal.
- Understanding pinocytosis regulation is crucial for cellular processes and drug delivery.
Purpose of the Study:
- To investigate how phorbol myristate acetate (PMA) influences pinocytosis in macrophages.
- To determine the effect of PMA on solute accumulation and transport kinetics.
Main Methods:
- Macrophages were stimulated with PMA and incubated with Lucifer Yellow (LY) to track pinocytosis.
- Kinetics of LY influx, accumulation, and efflux were measured under varying conditions and temperatures.
Main Results:
- PMA significantly increased macropinosome abundance and solute flow.
- LY accumulation was 4-6 times higher in PMA-stimulated macrophages.
- PMA enhanced LY efflux but increased influx even more, leading to greater net retention.
Conclusions:
- PMA stimulation enhances solute accumulation in macrophages via macropinocytosis.
- Increased size difference between pinosomes and efflux vesicles drives greater solute accumulation and membrane flow.
More Related Videos
Related Concept Videos
01:38Receptor-mediated Endocytosis
Overview
00:43Pinocytosis
Cells use energy-requiring bulk transport mechanisms to transfer large particles, or large amounts of small particles, into or out of the cell. The cells envelop the particles in spherical membranes called vesicles or vacuoles. Vesicles that transport material into the cell are built from the cell membrane. These vesicles encapsulate external molecules and transport them into the cell in a process called endocytosis.
00:38Pinocytosis
Cells use energy-requiring bulk transport mechanisms to transfer large particles or large numbers of small particles into or out of the cell. The cells envelop the particles in spherical membranes called vesicles or vacuoles. Vesicles that transport material into the cell are built from the cell membrane. These vesicles encapsulate external molecules and transport them into the cell in a process called endocytosis.
Pinocytosis ("cellular drinking") is one of three main types of endocytosis. In...
Pinocytosis ("cellular drinking") is one of three main types of endocytosis. In...
01:42Phosphoinositides 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...
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
01:11IP3/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...