Related Experiment Video
Updated: Jul 30, 2026
09:41
Isolation of Cellular Lipid Droplets: Two Purification Techniques Starting from Yeast Cells and Human Placentas
Published on: April 1, 2014
TIP47 is not a component of lipid droplets
1Department of Biochemistry, Stanford University School of Medicine, Stanford, California 95307, USA.
The Journal of Biological Chemistry
|April 21, 2001
Summary
TIP47 protein is crucial for transporting mannose 6-phosphate receptors but is not found in lipid droplets. Previous studies incorrectly identified TIP47 in lipid droplets due to antibody cross-reactivity.
Area of Science:
- Cell Biology
- Molecular Biology
- Protein Trafficking
Background:
- TIP47 protein mediates the transport of mannose 6-phosphate receptors.
- Mannose 6-phosphate receptors are essential for delivering lysosomal enzymes.
- Previous research suggested TIP47 is a lipid droplet-associated protein.
Purpose of the Study:
- To clarify the cellular localization of TIP47.
- To investigate the discrepancy regarding TIP47's presence in lipid droplets.
- To determine if TIP47 is associated with lipid droplets.
Main Methods:
- Antibody specificity testing using recombinant adipophilin.
- Immunological assays with antibodies specific to TIP47 residues 152-434.
- In vitro and in vivo functional assays for receptor transport.
Main Results:
- TIP47 specifically binds to mannose 6-phosphate receptors.
- Antibodies used in prior studies showed cross-reactivity with adipophilin and other proteins.
- TIP47 was confirmed not to be a constituent of lipid droplets.
Conclusions:
- TIP47 plays a vital role in endosome to trans-Golgi network transport of mannose 6-phosphate receptors.
- The previous association of TIP47 with lipid droplets was an artifact of antibody cross-reactivity.
- TIP47's function is related to receptor trafficking, not lipid droplet localization.
Related Concept Videos
01:38What are Lipids?
Overview
01:32Lipids as Anchors
In the plasma membrane, the lipids forming the bilayer can also act as an anchor to tether proteins to the membrane. The three main types of lipid anchors found in eukaryotes are – prenyl groups, fatty acyl groups, and glycosylphosphatidylinositol or GPI groups. Prenyl and fatty acyl groups act as anchors on the cytosolic surface of the membrane, whereas GPI anchors proteins on the extracellular side.
The carboxy-terminal of most of the prenylated proteins, such as Ras proteins, contains the...
The carboxy-terminal of most of the prenylated proteins, such as Ras proteins, contains the...
01:28Assembly of the Lipid Bilayer in the ER
Biological membranes are more than just a barrier separating cell cytoplasm from the outside environment. They are highly dynamic and help maintain the integrity and physiological stability of the cells as well as membrane-bound organelles. Membranes also play vital roles in cell-to-cell and intracellular communication.
A large chunk of any biological membrane is composed of phospholipids. These lipids have a heterogeneous distribution across different subcellular organelles and even between...
A large chunk of any biological membrane is composed of phospholipids. These lipids have a heterogeneous distribution across different subcellular organelles and even between...