Post translation control-regulation_of_gene_expression_in_eukaryotes - copy

Post-translational modification (PTM) refers to the covalent and generally enzymatic modification of proteins following protein biosynthesis. Proteins are synthesized by ribosomes translating mRNA into polypeptide chains, which may then undergo PTM to form the mature protein product. PTMs are important components in cell signaling, as for example when prohormones are converted to hormones.

1. POST TRANSLATION MODIFICATION(COVALENT MODIFICATION) -GENE EXPRESSION IN EUKARIYOTES NAME : DHRUVI SUVAGIYA CLASS : MSC SEM 3

2. A LITTLE BACKGROUND – GENE EXPRESSION IN EUKARYOTES

3. WHAT IS POST TRANSLATION MODIFICATION?? Post-translational modification (PTM) refers to the  covalent and generally enzymatic modification of  proteins Proteins are synthesized by ribosomes translating mRNA  into polypeptide chains, which may then undergo PTM to form the mature protein product. Post-translational modifications can occur on the amino acid side chains or at the protein's C- or N-  terminal. They can extend the 20 standard amino acids by modifying an existing functional group  or introducing a new one such as  phosphate, methane, lipid residues,etc.for regulating the activity of enzymes and is the most common post-translational.

4. WHY PTMs ARE NECESSARY?? Play a crucial role in generating the heterogeneity in proteins. Help in utilizing identical proteins for different cellular functions in different cell types. Regulation of particular protein sequence behaviour in most of the eukaryotic organisms. Play an important part in modifying the end product of expression. Contribute towards biological processes and diseased conditions. Translation of proteins across biological membranes.

5. TYPES OF PTMs??

6. COVALENT BOND MODIFICATION The proteins synthesized in translation are subjected to many covalent changes. By these modifications in the amino acids the proteins may be converted to active form or inactive form. These including,.. phosphorylation, glcosylation , methylation, alkaylation , lipoylation , sulfation , Carboxylation, acetylation.

7. Phosphorylation Addition of phosphate group to protein. Principally on serine, threonine or tyrosine residues. Also known as phospho regulation Play crucial role in cell growth , cell cycle , apoptosis and signal transduction .

8. Glycosylation The covalent attachment of oligosaccharides Addition of glycol group to protein. Principally on aspargine,hydroxylysine,serine or threonine . Play role in protein folding, conformation, distribution, stability and protein activity .

9. Methylation Addition of methyl group to protein Usually at lysine or arginine residues, Binds on nitrogen and oxygen of proteins Play role in histone methylation –important regulator of chromatin structure.

10. N-Acylation Addition of acetyl group at nitrogen group. Histone are acetylated on lysis residues in the n terminal tail as a part of gene regulation. Play role in regulation of transcription factors , effector proteins, molecular chaperon and cytoskeletoetal proteins . Methionine amino peptidase is an enzyme responsible for n terminal acetylation.

11. Disulphide bonding Covalent bond formed between two cysteine residues(R-S-S-R) These bonds contribute to the correct folding of protein as other elements of secondary structure.

12. Lipidation Attachment of lipid group (fatty acid)covalently to protein Play role in cellular localization, targeting signals, membrane structure and protein interactions .

13. DETECTION TECHNIQUE?? Mass spectrometry HPLC analysis Incorporation of radioactive group by addition to growing cell (75se labelling) Antibody cross reactivity(ab against phosphotyrosine) Gel electrophoresis.

14. REFFRENCES https://en.wikipedia.org/wiki/Post-translational_modification#:~:text=Post%2Dtranslational%20modification%20(PTM),of%20proteins%20following%20protein%20biosynthesis.&text=Other%20forms%20of%20post%2Dtranslational,removing%20the%20initiator%20methionine%20residue . https:// www.nature.com/articles/cr2013151 https://microbenotes.com/post-translational-modification/

15. THANK YOU