Related Experiment Video

Updated: Jul 31, 2026

An Adipocyte Cell Culture Model to Study the Impact of Protein and Micro-RNA Modulation on Adipocyte Function
09:20

An Adipocyte Cell Culture Model to Study the Impact of Protein and Micro-RNA Modulation on Adipocyte Function

Published on: May 4, 2021

Trafficking kinetics of the insulin-regulated membrane aminopeptidase in 3T3-L1 adipocytes

S A Ross1, J J Herbst, S R Keller

  • 1Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA.

Biochemical and Biophysical Research Communications
|November 5, 1997
PubMed

In fat and muscle cells insulin causes the marked translocation of the glucose transporter GLUT4 from its intracellular location to the plasma membrane. We and others have discovered an insulin-regulated membrane aminopeptidase (designated IRAP) that colocalizes with intracellular GLUT4 and also translocates markedly in response to insulin. This study describes the trafficking kinetics of IRAP in 3T3-L1 adipocytes. By means of a surface biotinylation method, the half-time for the increase in IRAP at the plasma membrane in response to insulin was found to be 2 min. The increase was completely blocked by the phosphatidylinositol 3-kinase inhibitor, wortmannin. In insulin-treated cells, biotinylated IRAP, initially at the plasma membrane, equilibrated with the intracellular pool with a half-time of 2 min. Thus, IRAP continuously recycles. Finally, vesicles isolated from the intracellular membranes with antibodies against IRAP and GLUT4 showed the same protein composition. In conjunction with results in the literature, these findings indicate that IRAP and GLUT4 traffic through the same intracellular compartments.

More Related Videos

Differentiated Mouse Adipocytes in Primary Culture: A Model of Insulin Resistance09:48

Differentiated Mouse Adipocytes in Primary Culture: A Model of Insulin Resistance

Published on: February 17, 2023

Measuring the Rate of Lipolysis in Ex Vivo Murine Adipose Tissue and Primary Preadipocytes Differentiated In Vitro09:41

Measuring the Rate of Lipolysis in Ex Vivo Murine Adipose Tissue and Primary Preadipocytes Differentiated In Vitro

Published on: March 17, 2023

Related Concept Videos

Translocation of Proteins into the Mitochondria01:19

Translocation of Proteins into the Mitochondria

Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Insulin Secretory Vesicles01:05

Insulin Secretory Vesicles

Insulin secretory vesicles release insulin to stimulate blood glucose uptake and regulate carbohydrate metabolism. When the blood glucose levels increase, glucose enters the pancreatic β-islet cells through glucose transporters. Once inside, glucose is metabolized through glycolysis, the citric acid cycle, and the electron transport chain, producing ATP. This increase in ATP concentration closes ATP-sensitive potassium channels, leading to depolarization of the membrane and the opening of...
Post-translational Translocation of Proteins to the RER01:27

Post-translational Translocation of Proteins to the RER

A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Insulin: The Receptor and Signaling Pathways01:28

Insulin: The Receptor and Signaling Pathways

Insulin action is mediated through a receptor tyrosine kinase, akin to the IGF-1 receptor. The number of receptors per cell varies significantly, from 40 on erythrocytes to 300,000 on adipocytes and hepatocytes. The insulin receptor consists of linked α/β subunit dimers, forming a heterotetramer glycoprotein with two extracellular α subunits and two β subunits spanning the membrane. The α subunits inhibit the inherent tyrosine kinase activity of the β subunits, but this inhibition is released...