When was the endoplasmic reticulum discovered?

The endoplasmic reticulum was discovered in 1945 by Keith Porter, Albert Claude, and Ernest Fullam. They were able to clearly observe the lacy membranes and vesicle-like bodies in cell culture studies using an electron microscope.

In 1953 Keith Porter applied the term ‘reticulum’ to their discovery. Reticulum is a Latin word that means 'network’. It appropriately describes the intricate network of membranes that make up this organelle. The term ‘endoplasmic’ refers to its position within the cell.

Further collaborations between Keith Porter and George Palade showed that endoplasmic reticulum is present in all eukaryotic cells. Ongoing studies resulted in more findings including the discovery of the smooth and rough ER, and their distribution in different types of cells.