Hustle-Bustle in the ER

What am I looking at?

This time-lapse video shows the dynamic structure of the endoplasmic reticulum within a kidney cell from a monkey. The ER is very densely packed near the nucleus, represented in this video by the bright orange color at the center of the cell, and is less dense toward the edges of the cell, as shown in darker orange. Click on the right arrow to see a second video showing a magnified view of the ER network toward the edges of the cell, seen in close to real time.

Biology in the background

The ER is the protein synthesis and processing center of a cell and is also responsible for the synthesis of some lipids. There are two types of ER in a cell – rough ER and smooth ER – that together form a single continuous membrane network within the cell’s cytoplasm. The rough ER membrane is studded with ribosomes, where proteins are synthesized. The smooth ER is where some lipids, phospholipids, and steroids are synthesized and some protein folding and processing occur. The rough ER is composed of an interconnected network of flattened, membrane-enclosed sacs known as cisternae. The smooth ER has a more interconnected tubular structure.

An ER tubule can range in size from 50 to 100 nanometers, or roughly 1,500 to 750 times smaller than the width of a human hair.

Technique

This video was created using confocal microscopy.