Endoplasmic reticulum

The endoplasmic reticulum (ER) is an extensive three-dimensional network that stretches from the inner nuclear envelope to the cell cortex with a single, continuous membrane and a single, continuous lumen. The ER contains specialized regions that carry out unique functions.

Types

 smooth endoplasmic reticulum (SER)
 rough endoplasmic reticulum (RER)

Pathology

 endoplasmic reticulum stress

• RNA translation diseases
  • Wolcott-Rallison syndrome

 endoplasmic reticulum retention

• alpha1-anti-trypsin deficiency (alpha1AT deficiency) variants exhibit a selective defect in migration of this secretory protein from the endoplasmic reticulum (ER) to Golgi apparatus.
• This is most marked for the PiZ polypeptide, attributable to a single amino acid substitution of Glu342 to Lys342. The mutant polypeptide (α1AT-Z) is abnormally folded, and polymerizes, causing its retention in the ER. All individuals with the PiZZ genotype accumulate α1AT-Z in the ER of hepatocytes.

See also

 cellular organelles
 reticulum endoplasmic stress
 ER protein transport

References

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