Function of golgi complex By KK Sahu Sir

Introduction
Discovery
Evolution
Structure
Function
Types of secretion are controlled by the Golgi complex
How do proteins move to the Golgi complex
Conclusion
Reference

1. function of Golgi complex By KAUSHAL KUMAR SAHU Assistant Professor (Ad Hoc) Department of Biotechnology Govt. Digvijay Autonomous P. G. College Raj-Nandgaon ( C. G. )

2. Synopsis Introduction Discovery Evolution Structure Function Types of secretion are controlled by the Golgi complex How do proteins move to the Golgi complex Conclusion Reference

3. Introduction The  Golgi apparatus  (also  Golgi body  or the  Golgi complex ) is an  organelle found in most  eukaryotic   cells .  It was discovered by the Italian physician Camillo Golgi , in 1897 after whom the Golgi apparatus is named. Golgi apparatus forms a part of the cellular  endomembrane system It provides connection between ER and perinuclear space on the one hand and between transport vesicles and plasma lemma on the other. It also performs an important function for transport of material from nucleus to the cytoplasm. It processes and packages  macromolecules , such as  proteins  and  lipids

4. DISCOVERY Due to its fairly large size, the Golgi apparatus was one of the first organelles to be discovered and observed in detail. The apparatus was discovered in 1897 by Italian  physician   Camillo Golgi  during an investigation of the  nervous system After first observing it under his  microscope , he termed the structure the internal reticular apparatus. The structure was then renamed after Golgi not long after the announcement of his discovery in 1898. However, some doubted the discovery at first, arguing that the appearance of the structure was merely an optical illusion created by the observation technique used by Golgi. With the development of modern microscopes in the 20th century, the discovery was confirm.

5. Evolution The Golgi apparatus appears to have existed even in the "ancestral eukaryote" from which all modern eukaryotes evolved, even though some do not have it in the stacked form.

6. Found in both plant and animal cells T he Golgi is composed of stacks of membrane-bound structures known as  cisternae  (singular:  cisterna ). An individual stack is sometimes called a dictyosome (from Greek  dictyon : net +  soma : body), [4]  especially in plant cell A mammalian cell typically contains 40 to 100 stacks. Between four and eight cisternae are usually present in a stack; however, in some  protists  as many as sixty have been observed Each cisterna comprises a flat, membrane enclosed disc that includes special Golgi enzymes. The cisternae stack has four functional regions: the cis- Golgi network, medial-Golgi, endo - Golgi, and trans-Golgi network . Each region contains different enzymes . STRUCTURE This electron micrograph illustrates a Golgi Complex

7. Micrograph of Golgi apparatus, visible as a stack of semicircular black rings near the bottom. Numerous circular vesicles can be seen in proximity to the organelle Diagram of secretory process from endoplasmic reticulum (orange) to Golgi apparatus (pink). 1. Nuclear membrane; 2. Nuclear pore; 3. Rough endoplasmic reticulum (RER); 4. Smooth endoplasmic reticulum (SER); 5. Ribosome attached to RER; 6. Macromolecules; 7. Transport vesicles; 8. Golgi apparatus; 9. Cis  face of Golgi apparatus; 10.  Trans  face of Golgi apparatus; 11. Cisternae of lipids

8. Function This includes the production of  glycosaminoglycans  (GAGs), long unbranched polysaccharides  . Enzymes in the Golgi  polymerize  several of these GAGs via a  xylose   link onto the core protein Another task of the Golgi involves the  sulfation  of certain molecules passing through its lumen via sulphotranferases that gain their sulphur molecule from a donor called PAPs. This process occurs on the GAGs of proteoglycans as well as on the core protein. The level of sulfation is very important to the proteoglycans' signalling abilities as well as giving the proteoglycan its overall negative charge. [13] The phosphorylation of molecules requires that  ATP  is imported into the  lumen  of the Golgi [15]  and then utilised by resident  kinases  such as casein kinase 1  and  casein kinase 2   One molecule that is phosphorylated in the Golgi is  Apolipoprotein , which forms a molecule known as VLDL  that is a constituent of  blood serum . It is thought that the phosphorylation of these molecules is important to help aid in their sorting for secretion   into the blood serum. A newly characterized protein, GAAP (Golgi anti-apoptotic protein), almost exclusively resides in the Golgi and protects cells from apoptosis The bcl2 genes present in the Golgi are used for this purpose.

9. Types of secretion are controlled by the Golgi complex The Golgi complex controls trafficking of different types of proteins. Some are destined for secretion. Others are destined for the extracellular matrix. other proteins, such as lysosomal enzymes, may need to be sorted and sequestered from the remaining constituents because of their potential destructive effects.

10. Finally, this cartoon also shows the packaging of lysosomes .

11. Transport of material in and out of the Golgi complex involves budding and fusion of vesicles. This cartoon shows that the membranes of each join and align themselves during the process so that the inside face remains in the lumen and the outside face remains towards the cytoplasm. How do proteins move to the Golgi Complex?

12. Conclusion The golgi apparatus is an important organelle of eukaryotic cells . directing the carbohydrates and protein required by the body to their correct destination is the primary job of golgi body. In this process of directing molecules to appropriate destinations, they are tagged with destination information and structural modifications.

13. Reference 1.Lodish et al.-molecular cell biology 2.P.K. Gupta, cell and molecular biology 3.C.B. Powar , cell biology 4.Internet.