The Golgi body is a cell organelle found in most eukaryotic cells. Also known as the Golgi complex or the Golgi apparatus, this organelle was first discovered by Italian physician, Carmillo Golgi in 1897, after whom it has been named. It is found in both plants and animals and is composed of stacks of membrane-bound structures known as cisternae.
The main Golgi body function is secretion of enzymes and hormones. According to scientific studies, the organelle modifies new proteins synthesized by the endoplasmic reticulum present in the cytoplasm, processes and then sorts them out for transportation. The transportation of lipids or proteins is also controlled by the Golgi complex which helps in the formation of lysosomes. Lysosomes take part in intercellular digestion. Thus, the organelle can be compared to the shipping and receiving department of a large company.
The Golgi apparatus also takes part in the synthesis of proteoglycans, which are molecules present in the extracellular matrix of animals. It is the major site of carbohydrate synthesis. Another Golgi body function is the sulfation(a phase-II enzyme reaction) of certain molecules passing through its lumen via sulphotranferases that gain their sulphur molecules from a donor called PAPs.
The phosphorylation of molecules require ATP(Adenosine Triphosphate),a kind of energy, which is imported in the lumen of the Golgi and then utilized by resident kinases(a type of enzyme) such as casein kinase 1 and casein kinase 2.
The Golgi has a putative role in apoptosis (a process of Programmed Cell Death-PCD) with several Bcl-2, an apoptosis regulator protein, family members localized there, as well as to the mitochondria, which is the power house of a cell providing it with energy. A newly characterized protein GAAP (Golgi anti-apoptotic protein), almost resides in the organelle, and protect cells from apoptosis by an yet undefined mechanism.
The Golgi complex disappears during mitosis, the cell division occurring to repair damaged cell or replace worn-out cells. It, again, appears after the cell division during telophase (the last stage of mitosis) though it is still not known how this occurs.
Within the Golgi complex, various chemical groups are added to the macromolecules to ensure that they reach the proper destination. In this way the Golgi attaches an ‘address' to each macromolecule it receives. Thus, this is another Golgi body function.
Thus, the Golgi body helps the cell by taking part in protein synthesis and carbohydrate synthesis. It helps in secretion. Lysosomes are formed by the organelles transported lipids, which takes part in intercellular digestion. Though the Golgi body was one of the first cell organelle discovered (for its large size), still there are certain undiscovered characteristics of this vital cell organelle.