Monkey Kidney Cells with mEmerald-PMP and mApple-ER
The endoplasmic reticulum functions as a storage unit for integral membrane proteins as they are being synthesized. Glycosylation, disulfide bond formation and rearrangement, and drug metabolism are a few other functions it performs. The term endoplasmic reticulum translates literally to "little net within the cytoplasm". The organelle is present in all eukaryotic cells, where the ER functions primarily in protein modification, the production of lipids and macromolecules, and the distribution of cellular materials. In the digital video sequence in this section, monkey kidney epithelial cells (BS-C-1 line) can be seen expressing mApple fused to the endoplasmic reticulum and mEmerald fused to peroxisomes.
The green fluorescent protein employed in this video sequence, mEmerald, was developed from an enhanced form of Aequorea GFP. mEmerald is relatively bright and photostable, but exhibits a fast photobleaching component that can be problematic in certain applications. mApple is one of the red-emitting mFruit fluorescent proteins derived from mRFP1 through the use of a directed evolution approach.