Related Experiment Video

Updated: Aug 4, 2026

Live Cell Calcium Imaging Combined with siRNA Mediated Gene Silencing Identifies Ca2+ Leak Channels in the ER Membrane and their Regulatory Mechanisms
13:40

Live Cell Calcium Imaging Combined with siRNA Mediated Gene Silencing Identifies Ca2+ Leak Channels in the ER Membrane and their Regulatory Mechanisms

Published on: July 7, 2011

Regulation of caveolin and caveolae by cholesterol in MDCK cells

D Hailstones1, L S Sleer, R G Parton

  • 1The Heart Research Institute, Camperdown NSW, Sydney, Australia.

Journal of Lipid Research
|March 21, 1998
PubMed

Insights

Cellular cholesterol levels significantly impact caveolin expression and caveolae formation. Depleting cholesterol reduces caveolin mRNA and protein, hindering caveolae development and suggesting a role in cholesterol homeostasis.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Caveolins are integral membrane proteins crucial for forming caveolae, flask-shaped invaginations of the plasma membrane.
  • Caveolae are implicated in various cellular processes, including endocytosis, signal transduction, and lipid transport.
  • The precise role of cellular cholesterol in regulating caveolin expression and caveolae biogenesis remains incompletely understood.

Purpose of the Study:

  • To investigate the relationship between cellular cholesterol concentration and caveolin expression in MDCK cells.
  • To determine the effect of cholesterol depletion and enrichment on caveolin mRNA and protein levels.
  • To examine the impact of altered cholesterol levels on the formation and morphology of caveolae.

Main Methods:

  • MDCK cells were treated with simvastatin (cholesterol synthesis inhibitor) or beta-trimethyl cyclodextrin (cholesterol sequestering agent) to deplete cellular cholesterol.
  • 25-hydroxycholesterol was used to investigate the effect of cholesterol enrichment.
  • Caveolin mRNA levels were quantified using RT-PCR.
  • Caveolin protein levels were assessed by Western blotting and indirect immunofluorescence.
  • Quantitative electron microscopy was employed to analyze caveolae morphology and number.

Main Results:

  • Simvastatin and beta-trimethyl cyclodextrin treatment reduced caveolin mRNA levels to one-sixth of control values.
  • Both treatments decreased total cellular cholesterol by approximately 50%.
  • Caveolin protein concentration also decreased by 50% in cholesterol-depleted cells, leading to severe attenuation of caveolin expression.
  • Quantitative electron microscopy revealed a complete loss of recognizable invaginated caveolae upon cholesterol depletion.
  • A threshold phenomenon was observed, indicating caveolae formation requires cellular cholesterol levels above 50% of control values.
  • 25-hydroxycholesterol did not directly regulate caveolin mRNA levels.

Conclusions:

  • Cellular cholesterol concentration critically regulates caveolin expression and caveolae formation.
  • Caveolin expression and caveolae biogenesis are dependent on maintaining a sufficient level of cellular cholesterol.
  • These findings suggest that caveolins and caveolae play a significant role in cellular cholesterol homeostasis.

More Related Videos

Cholesterol Efflux Assay07:54

Cholesterol Efflux Assay

Published on: March 6, 2012

Enrichment of Mammalian Tissues and Xenopus Oocytes with Cholesterol10:12

Enrichment of Mammalian Tissues and Xenopus Oocytes with Cholesterol

Published on: March 25, 2020

Related Concept Videos

Membrane Domains01:18

Membrane Domains

The membrane domains concentrate specific lipids and proteins at one place within the membrane, which helps in cell signaling, adhesion, and other critical cellular processes. These domains can differ in size, composition, function, and lifespan.
Protein Domains
The membrane comprises a group of distinct proteins responsible for carrying out a cell's specific function. For example, the plasma membrane of the human sperm, or a single germ cell, contains a unique set of proteins in the anterior...
Intralumenal Vesicles and Multivesicular Bodies01:38

Intralumenal Vesicles and Multivesicular Bodies

Intraluminal vesicles (ILVs) are small vesicles 50-80 nm in diameter formed during the maturation of early endosomes. A specialized endosome containing numerous ILVs is called a multivesicular body (MVB). ILVs contain internalized molecules such as antigens, nucleic acids, proteins, and metabolites. Some of these molecules are released from the MVBs inside exosomes and are transported to other cells. Other MVBs contain molecules that are retained in the ILVs and are later degraded within the...
Overview of Secretory Vesicles01:33

Overview of Secretory Vesicles

Secretory vesicles, also known as dense core vesicles (DCVs), are membrane-bound vesicles that transport secretory proteins, such as hormones or neurotransmitters. Regulated secretory vesicles transport proteins from the trans-Golgi network to the exterior of the cell. Proteins present in regulated secretory vesicles are required to be rapidly exocytosed in large amounts upon a specific stimulus.
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Regulation of Nuclear Protein Sorting01:45

Regulation of Nuclear Protein Sorting

Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...
Receptor Downregulation in MVBs01:15

Receptor Downregulation in MVBs

Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that  lead to cell proliferation, migration, and differentiation. Overexpression of EGFR  stimulates cells to proliferate. Excessive  EGFR activation may...
Cholesterol: Significance and Regulation01:29

Cholesterol: Significance and Regulation

Although not a source of energy, cholesterol plays a significant role as a foundational structure for bile salts, steroid hormones, and vitamin D, as well as being a crucial component of plasma membranes. Approximately 15% of blood cholesterol is derived from our diet, with the remainder synthesized from acetyl CoA by the liver and intestines. Cholesterol is eliminated from the body through its conversion into bile salts, which are eventually discarded in the feces.
Considering cholesterol and...