Related Experiment Videos
Caveolar internalization of growth hormone
P E Lobie1, R Sadir, R Graichen
1National University of Singapore, 30 Medical Drive 117609, Singapore, Republic of Singapore. mcbpel@mcbsgs1.imcb.nus.sg
Experimental Cell Research
|January 12, 1999
Summary
Caveolae, specialized cell structures, facilitate the internalization of growth hormone (GH) in cells. Disrupting caveolae partially inhibits GH uptake, indicating their crucial role in this process.
Area of Science:
- Cell Biology
- Molecular Endocrinology
- Membrane Trafficking
Background:
- Caveolae are cholesterol-dependent plasma membrane invaginations.
- Caveolin proteins are essential structural components of caveolae.
- The role of caveolae in growth hormone (GH) internalization is not well understood.
Purpose of the Study:
- To investigate the role of caveolae in the internalization of GH.
- To determine if GH receptors localize to caveolae.
- To assess the impact of caveolae disruption on GH uptake.
Main Methods:
- Immunogold electron microscopy to visualize GH receptor and caveolin localization.
- Use of sterol-binding and non-sterol-binding agents to disrupt caveolae.
- Transient transfection of caveolin and GH receptor cDNA in CHO cells.
- Measurement of 125I-hGH internalization.
Main Results:
- GH receptor and GH aggregate in caveolae upon GH stimulation.
- GH is internalized within caveolin-containing vesicles.
- Disruption of caveolae by sterol-binding agents partially inhibits GH internalization.
- Increased caveolin expression enhances GH internalization and signaling.
Conclusions:
- Caveolae represent a significant pathway for GH internalization.
- This mechanism may be conserved for other cytokine receptor superfamily members.
- Caveolae play a direct role in regulating GH uptake and signaling.