[2] Because of its large size and distinctive structure, the Golgi apparatus was one of the first organelles to be discovered and observed in detail.

[3][2] After first observing it under his microscope, he termed the structure as apparato reticolare interno ("internal reticular apparatus").

Some doubted the discovery at first, arguing that the appearance of the structure was merely an optical illusion created by Golgi’s observation technique.

In experiments it is seen that as microtubules are depolymerized the Golgi apparatuses lose mutual connections and become individual stacks throughout the cytoplasm.

[5][10] The Golgi apparatus is a major collection and dispatch station of protein products received from the endoplasmic reticulum.

In this respect, the Golgi can be thought of as similar to a post office: it packages and labels items which it then sends to different parts of the cell or to the extracellular space.

Individual stacks have different assortments of enzymes, allowing for progressive processing of cargo proteins as they travel from the cisternae to the trans Golgi face.

[5][10] Enzymatic reactions within the Golgi stacks occur exclusively near its membrane surfaces, where enzymes are anchored.

[5] Other general post-translational modifications of proteins include the addition of carbohydrates (glycosylation)[12] and phosphates (phosphorylation).

This area of the Golgi is the point at which proteins are sorted and shipped to their intended destinations by their placement into one of at least three different types of vesicles, depending upon the signal sequence they carry.

Among the fundamental unanswered questions are the directionality of COPI vesicles and role of Rab GTPases in modulating protein cargo traffic.

[14] Brefeldin A (BFA) is a fungal metabolite used experimentally to disrupt the secretion pathway as a method of testing Golgi function.

[17] ARFs are small GTPases which regulate vesicular trafficking through the binding of COPs to endosomes and the Golgi.

[17] BFA inhibits the function of several guanine nucleotide exchange factors (GEFs) that mediate GTP-binding of ARFs.