Related Experiment Video
Updated: Aug 12, 2026
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
Insulin provokes apparent increases in rat adipocyte M-kinase
T Ishizuka1, D R Cooper, R V Farese
1James A. Haley Veterans' Hospital, Tampa, FL 33612.
Biochemical and Biophysical Research Communications
|June 29, 1990
Summary
Insulin triggers changes in protein kinase C (PKC) within rat fat cells. This study reveals insulin increases M-kinase activity by altering PKC forms, impacting cellular signaling.
Area of Science:
- Cellular biology
- Molecular endocrinology
- Signal transduction
Background:
- Insulin is a key metabolic hormone regulating glucose uptake in adipocytes.
- Protein kinase C (PKC) is involved in various cellular processes, including insulin signaling.
- Previous studies indicated insulin stimulates PKC translocation in rat adipocytes.
Purpose of the Study:
- To investigate the specific effects of insulin on protein kinase C (PKC) forms and activity in rat adipocytes.
- To elucidate the relationship between insulin, cytosolic PKC changes, and M-kinase activity.
Main Methods:
- Isolation of rat adipocytes.
- Measurement of cytosolic protein kinase C (PKC) levels and activity.
- Assessment of Ca++/phospholipid-independent protein kinase activity.
- Immunological detection of PKC-related proteins using anti-PKC antiserum.
Main Results:
- Insulin stimulation led to a decrease in the 80 kDa cytosolic PKC.
- An increase in Ca++/phospholipid-independent protein kinase activity was observed.
- A concurrent rise in a 50 kDa cytosolic protein, recognized by anti-PKC antiserum, was detected.
- These alterations suggest a shift in PKC-related kinase activity.
Conclusions:
- Insulin induces significant modifications in the cytosolic protein kinase C (PKC) profile in rat adipocytes.
- The observed changes indicate that insulin promotes an increase in M-kinase activity.
- These findings contribute to understanding the intricate mechanisms of insulin action at the cellular level.
Related Concept Videos
01:05Insulin 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...
01:22PI3K/mTOR/AKT Signaling Pathway
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast, mTORC2 consists of a rapamycin-insensitive companion...
01:25cAMP-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,...
01:16Hormones Regulating Blood Glucose
Insulin is released by beta cells of the pancreas when blood glucose levels are high. It facilitates glucose absorption and utilization in insulin-dependent cells with insulin receptors on their plasma membranes. Insulin promotes glucose uptake by increasing the number of glucose transport proteins in the cell membrane, allowing glucose to enter the cell. As a result, glucose utilization and ATP production are enhanced.
In addition to accelerating glucose uptake and utilization, insulin has...
In addition to accelerating glucose uptake and utilization, insulin has...
01:27Glucose Homeostasis: Pancreatic Islets and Insulin Secretion
The pancreatic islets comprising only 1%-2% of the volume are highly vascularized and innervated mini-organs. They contain five endocrine cell types, including β cells that secrete insulin, which is synthesized as a single polypeptide chain, preproinsulin, processed to proinsulin, and finally to insulin and C-peptide. This process is complex and regulated, involving the Golgi complex, the endoplasmic reticulum, and the secretory granules of the β cell.
Insulin and C-peptide are co-secreted in...
Insulin and C-peptide are co-secreted in...
01:28Insulin: 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...