While it is unclear how molecules move between adjacent Golgi cisternae, it is apparent that the molecules move from cis- cisterna, the entry face, to the trans- cisterna, the exit face. Experiments initially suggested vesicles that bud from one cisterna and fuse with the next cisterna to transport proteins between the cisternae. This vesicular transport model describes the Golgi apparatus as a relatively static structure with a unique enzyme composition in each cisterna. Molecules are...

Secretory vesicles, also known as dense core vesicles (DCVs), are membrane-bound vesicles that transport secretory proteins, such as hormones or neurotransmitters. Regulated secretory vesicles transport proteins from the trans-Golgi network to the exterior of the cell. Proteins present in regulated secretory vesicles are required to be rapidly exocytosed in large amounts upon a specific stimulus.
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...

Tail-anchored, or TA, proteins are estimated to make up to 3-5% of membrane proteins found in the eukaryotic cell. Such proteins have a single transmembrane domain located approximately 30 amino acid residues upstream from the C-terminal end. As a result, the signal recognition particle (SRP) cannot guide a TA protein to the ER membrane for cotranslational insertion. Hence, they are integrated into the ER membrane post-translationally using their C-terminal end as the anchor. TA proteins...

Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of...

Properly folded and assembled proteins are selectively packaged into vesicles that exit the ER. Motor proteins transport these vesicles to the Golgi apparatus for adding modifications that make these proteins functional at their destination.
The Golgi apparatus is a eukaryotic organelle that has a distinctive ribbon-like appearance. It is a primary sorting and dispatch station for cargo arriving from the ER. Newly arriving vesicles enter the cis face of the Golgi, closest to the ER, and are...

Golgi matrix proteins are a group of highly dynamic proteins that maintain the stacked structure of Golgi. These proteins adapt to rapid morphological changes of the Golgi during the cell cycle. During cell division, mild proteolysis removes these connections resulting in Golgi unstacking. In The daughter cells, these proteins help reassemble the unstacked Golgi.
One of the first identified Golgi matrix proteins was GM130, a rod-like protein located in the cis-Golgi. Subsequently, many Golgi...