P53 apoptosis

Genetic information is stored in DNA by means of a triplet code that is nearly universal to all living things on Earth.

1. P53- Apoptosis Presented by : Anfal ALKATEEB

2. Introduction In 2012, an estimated 14.1 million new cases of cancer occurred worldwide. Out of 10 deaths 4 from cancer • What is cancer ? Who controls cancer in our body? Now

3. What is cancer ? . Cancer • Single type of cell proliferate continuously becomes immortal further into a tumor. • Two types of tumor Benign Tumor . Malignant Tumor Out of 10 deaths 4 from cancer • There are 100 different forms of cancer. • Most common types of cancer are lung, breast, bowel and prostate which accounts for 4 death in 10 cancer patients • Lung cancer is common in Men’s and Breast cancer in Female

4. Who controls cancer in our body? P53 as a Guardian angel of the genome . Has been described as Guardian angel of the genome it performs flowing mechanism : DNA repair Cell growth arrest . Apoptosis cell programmed cell death. P53 is also known as cellular tumor Antigen Ag, phosphoprotein P53 or tumor suppressor p53. P53 protein is encoded by TP53.

5. P53 discovering The name p53 was given in 1979 describing the apparent molecular mass; SDS-PAGE analysis indicates that it is a 53-kilodalton ( kDa ) protein. The actual mass of the full-length p53 protein (p53α) based on the sum of masses of the amino acid residues is only 43.7 kDa

6. Overview DNA damage Trigger expression of P53 gene Increased P53 levels Prevent cell form entering S phase of cell cycle Arrest of cell cycle at G1 phase Allow time for the DNA repair to take place P53 Induces DNA repair gene DNA not repair Apoptosis Permanent arrest \ senescence DNA repaired P53 degrades Cell cycle continue Conserve stability Gradient of genome

7. What is : P53 ( phosphoprotein p53) This difference is due to the high number of proline residues in the protein, which slow its migration on SDS-PAGE, thus making it appear heavier than it actually is . The human TP53 gene encodes at least 15 protein isoforms, ranging in size from 3.5 to 43.7 kDa . All these p53 proteins are called the p53 isoforms.

8. P53 roles transformation-related protein 53 (TRP53 ), is any isoform of a protein encoded by homologous genes in various organisms, such as TP53 (humans) and Trp53 (mice). This homolog (originally thought to be, and often spoken of as, a single protein) is crucial in multicellular organisms, where it prevents cancer formation, thus, functions as a tumor suppressor. p53 has been described as "the guardian of the genome" because of its role in conserving stability by preventing genome mutation .

9. The TP53 gene is the most frequently mutated gene (>50%) in human cancer, indicating that the TP53 gene plays a crucial role in preventing cancer formation. TP53 gene encodes proteins that bind to DNA and regulate gene expression to prevent mutations of the genome.

10. Type and p53 rule

11. Protein 53 structure TP53 gene is located on the short arm of chromosome 17 (17p13.1) • he p53 protein is active as a tetramer of 4 chains of 393 amino acids. Each chain has several domains . At the N-terminal there are two distinct transactivation domains (TADI and TADII), a nuclear export signal (NES) followed by the proline rich domain (PD) and the DNA binding domain (DBD).

12. Then at the C-terminus there is an oligomerization domain (OD), three nuclear localization signals (NLS), a second NES and a lysine rich regulatory domain (RD ). The TADI (residues 1-42) and TADII (residues 43-62) are critical for p53’s regulation since they provide binding sites for the transcriptional machinery and the negative regulator MDM2 - they are differentially involved in the activation of a distinct set of p53 target genes .

13. The exact function of the PD (residues 63-97) is not well understood but the high proline frequency is conserved though species . Additionally, from research using mouse models it is also known that the length of the PD is critical to maintain p53’s tumor suppressive function, and the domain also contains a common single nucleotide polymorphism (SNP) at codon 72 again highlighting the significance of this region.

14. The DBD (residues 102-292) is pivotal for the transcriptional activity of p53. It contains 4 of the 5 conserved boxes in p53. The OD (residues 323-356) allows p53 to form a tetramer which is organized as a dimer of dimers . The C-terminus of p53 contains a cluster of three NLSs that mediate the nuclear location of the protein. These sequences bind to specific receptors and allow selective passage of p53 through the nuclear pore complex . The C-terminal NES, a highly conserved region has been shown to be essential for nuclear export of p53. Both the NLS and NES regions are required for nuclear-cytosolic shuttling of p53 as a means to regulate p53 transcriptional function

15. Apoptosis introduction Cell death is part of normal development and maturation cycle, and is the component of many response patterns of living tissues to xenobiotic agents (i.e. micro organisms and chemicals ) and to endogenous modulations, such as inflammation and disturbed blood supply .

16. Cell death is an important variable in cancer development, cancer prevention and cancer therapy. In the treatment of cancer, the major approach is the removal, by surgery, of the neoplasm and/or the induction of cell death in neoplastic cells by radiation, toxic chemicals, antibodies and/or cells of the immune system

17. On the other hand, this path biological process remains poorly understood and the physiological and biochemical factors that lead to cell death are still not clear.

18. One main factor is the existing confusion between ‘ apoptosis’ process, as compared and contrasted with ‘ necrosis’, leading to the overlapping of the ante mortem changes, i.e. the process of cell death, and the post-mortem changes, i.e. the necrosis process. What is Apoptosis

19. Apoptosis , also known as programmed cell death, is characterized by specific morphological and biochemical changes. In most cases, physiological cell death occurs by apoptosis as opposed to necrosis. The term ‘ apoptosis’, defined as a controlled type of cell death that can be induced by a variety of physiologic and pharmacological agents. Apoptosis is controlled by What is Apoptosis Intrinsic pathway extrinsic pathway caspases

20. Apoptosis controlled by

21. Apoptosis On the basis of the following main morphological criteria: cellular shrinkage, condensation and margination of the nuclear chromatin, DNA fragmentation, cytoplasmic vacuolation , cell lysis.

22. Apoptosis mechanisms Apoptos is : before cell’s destruction, cell must be given its orders ): Apoptosis : in three steps. initiation by two different mechanisms , depending whether the initiate signal come from outside or from inside the cell Execution. Phagocytosis.

23. Apoptosis Mechanisms Intrinsic pathway . The mitochondria in the cell keep it alive by aerobic breathing (providing oxygen to the cells). extrinsic pathway activation mechanism is when receptors bind within the cell and open up the mitochondrial pores . When this happens, it causes a balance of pro- apoptoic proteins and anti-apoptotic proteins, allowing the process to activate . Lead to activation of Execution is caspases

24. extrinsic pathway Death Receptors- cell surface receptor that transmit apoptotic signals, initiated by ligands Ligands: Fas ligand, Tumor Necrosis Factor (TNF) alpha, and Tumor necrosis (TNF)-related apoptosis-inducing ligand TRAIL . Lead to generation of ceramide Result in large number of clustering of death receptors.

25. Death domain. Conformation change in the intracellular domain of the receptor . Allows recruitment of various apoptotic proteins to the receptor. Final step- recruitment of caspase 8. Resulting the activation of caspase 8 and the initiation of apoptosis.

26. Apoptosis mitochondria pathway 1. Apoptotic proteins cause mitochondria to swell up, opening their pores .( in the cytosol of cell it contains proteins which stop apoptosis from happening) 2. mitochondria pores open up: they release mitochondrial proteins which bind with these other proteins . Mit . Protein is known SMACs

27. Mitochondria contains proteins like Apoptosis Inducing Factor (AIF), Smac / DIABLO and Cytochrome C that regulate cell death. These proteins are release through the a pore called Permeability Transition (PT) pore. The release of Cytochrome leads to recruitment of pro-caspase 9 and Apoptotic protease activating factor 1 ( Apaf-1 ). This forms the apoptosome . Intrinsic pathway of apoptosis

28. Controlled of apoptosis

29. Mechanism (Intrinsic) cont. This is follow by the activation of caspase 9 which in turn result with the induction of apoptosis. Most Important player Prote ases Asp artate –direction C ysteine– dependent Caspases Caspases : are a family of protease enzymes playing essential roles in programmed cell death and inflammation:

30. Types of caspases Initiator caspases Executioner caspases

31. All types of ( initiator and executioner) caspases are in inactive form , these are called procaspases. The initiato r caspases are activated by extrinsic pathway and intrinsic pathway. The executioner caspases are activated by intrinsic pathway.

32. Caspases After forming a complex between Death Domain & Fas Associated Death Domain, the. procaspases8 will activate Activated caspase 8 Activated caspase 3,6& 7

33. Nuclear breakdown by endonuclease activation & breakdown cytoskeleton. After that formed apoptotic body have receptors to macrophage lead to phagocytosis

34. Your