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Updated: Jun 30, 2026
13:13
Nano-fEM: Protein Localization Using Photo-activated Localization Microscopy and Electron Microscopy
Published on: December 3, 2012
Summary
Albumin synthesis occurs in rat hepatocytes via bound polysomes, directly entering the cytosol. This challenges the established theory of albumin transport through the endoplasmic reticulum and Golgi apparatus.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- The established theory posits albumin is synthesized by ribosomes bound to the endoplasmic reticulum.
- This process involves transport through the endoplasmic reticulum and Golgi apparatus.
Purpose of the Study:
- To investigate the cellular site and pathway of albumin synthesis in rats.
- To challenge and refine the existing understanding of albumin biosynthesis.
Main Methods:
- Microscopic examination of rat hepatocytes.
- Analysis of albumin synthesis in various rat tissues and cell types.
Main Results:
- Albumin molecules were observed to be synthesized by bound polysomes on the endoplasmic reticulum and nuclear envelope in light hepatocytes.
- Synthesized albumin was directly discharged into the cytosol and then to extracellular spaces.
- Positive albumin synthesis activity was also detected in rat aorta, kidney, and hepatoma cells, contradicting previous findings.
Conclusions:
- Albumin is synthesized in the cytosol, not solely within the endoplasmic reticulum-Golgi pathway.
- Albumin synthesis is not exclusive to liver cells, with activity found in other tissues like the aorta and kidney.
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