Endoplasmic reticulum
The endoplasmic reticulum (ER) is a system of intracellular unit membranes. Regions of the endoplasmic reticulum with ribosomes are called rough endoplasmic reticulum (RER), while regions lacking ribosomes are termed smooth endoplasmic reticulum (SER).
RER >
The RER consists of flattened, interconnected membranous sacs (cisterns) that are continuous with the nuclear envelope. RER possesses ribosomes for synthesis of proteins for export, membrane insertion and incorporation into lysosomes. Proteins synthesized on the RER either accumulate in the central space of the cisterns or are inserted into the ER membrane during translation. Newly synthesized proteins are transported to the Golgi apparatus in vesicles that bud off the RER.
- Ribosomes on RER
The RER consists of flattened, interconnected membranous sacs (cisterns) that are continuous with the nuclear envelope. RER possesses ribosomes for synthesis of proteins for export, membrane insertion and incorporation into lysosomes. Proteins synthesized on the RER either accumulate in the central space of the cisterns or are inserted into the ER membrane during translation. Newly synthesized proteins are transported to the Golgi apparatus in vesicles that bud off the RER.
Connection with nuclear envelope
The RER consists of flattened, interconnected membranous sacs (cisterns) that are continuous with the nuclear envelope. RER possesses ribosomes for synthesis of proteins for export, membrane insertion and incorporation into lysosomes. Proteins synthesized on the RER either accumulate in the central space of the cisterns or are inserted into the ER membrane during translation. Newly synthesized proteins are transported to the Golgi apparatus in vesicles that bud off the RER.
SER >
SER consists of branched tubules of unit membranes that are continuous with the RER. SER lacks ribosomes and functions in lipid synthesis, detoxification and calcium storage.
