Cyclin dependent kinases
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Cyclin-dependent kinases (CDKs) are protein kinases that regulate critical cellular processes such as the cell cycle, transcription, and differentiation. CDKs are activated when bound to cyclin proteins and phosphorylate target proteins to regulate their activity. Different cyclin-CDK complexes are involved at different phases of the cell cycle, controlling checkpoints and ensuring DNA replication only occurs once per cycle. When DNA damage is detected, CDK inhibitors like p53 and p21 are activated, halting transcription and giving time for DNA repair.
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GENERAL IDEA OF SIGNAL TRANSDUCTION
DEFINATION
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HISTORY
BASIC ELEMENTS IN SIGNAL TRANSDUCTION
TYPES OF SIGNAL TRANSDUCTION
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Cell Cycle_ Usman.pptx sasgdgdb vdf g g rg gmunshi5
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The cell cycle is regulated by cyclins, cyclin-dependent kinases (CDKs), and tumor suppressors. The M phase is the shortest phase and includes mitosis and cytokinesis. G1 phase duration is variable. CDKs must bind to cyclins to transition between phases and are inhibited by CDK inhibitors in the presence of errors. The Cyclin D/Cdk4 complex initiates DNA replication by phosphorylating the retinoblastoma protein (pRb). The p53 tumor suppressor inhibits DNA replication through activating pRb and initiating apoptosis in cells with irreparable DNA damage.More Related Content
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油
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TERMENOLOGY
SITES OF HOLLIDAY JUNCTION
HOMOLOGOUS RECOMBINATION
HOLLIDAY MODEL
DOUBEL STRAND BREAK MODEL
IN PROKAYOTIC RECOMBINATION
IN EUKARYOTIC RECOMBINATION
SITE SPECIFIC RECOMBINATION
SERINE RECOMBINATION
TYROSINE RECOMBINATION
TRANSPOSITION
ILLEGITIMATE RECOMBINATION
CONCLUSION
REFRENCES
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油
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Purification
History
PRODUCTS OF RNAP
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Non-coding RNA 油or "RNA genes
Transfer RNA
Ribosomal RNA
Micro RNA
Catalytic RNA (Ribozyme)
prokaryotic and eukaryotic
Transcription by RNA Polymerase
TYPES OF RNA POLYMERASE
Type I
Type II
Type III
Prokaryotic Transcription Unit
EXPRESSION OF A PROKARYOTIC GENE
Prokaryotic Polycistronic Message Codes for Several Different Proteins
Eukaryotic Transcription Unit
ENHANCERS AND SILENCERS
RESULT OF THE TRANSCRIPTION CYCLE
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These are also known as Jumping genes.
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油
This document discusses site-specific recombination, including the structures and mechanisms involved. It describes two classes of recombinases - tyrosine recombinases and serine recombinases. Tyrosine recombinases involve cleavage of DNA through formation of a protein-DNA bond using a tyrosine residue. Serine recombinases utilize a phosphoserine bond between DNA and a conserved serine residue. The document provides examples of applications for site-specific recombination such as tracking cell lineage, altering gene expression, and targeted gene knockout.Ribozyme
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油
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- Common ribozyme activities include splicing and cleaving RNA and DNA. Ribozymes in the ribosome help link amino acids during protein synthesis.
- Major types of ribozymes include group I and group II introns, hammerhead, hairpin, and RNase P ribozymes. They use mechanisms like metal ion coordination and nucleophilic attacks to catalyze reactions.
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油
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油
1. There are four main models of DNA replication: rolling circle replication, theta replication, bidirectional replication of linear DNA, and telomere replication.
2. Rolling circle replication involves nicking circular DNA and using one strand as a template to produce multiple copies of the original circular DNA.
3. Theta replication occurs in prokaryotes and involves unwinding circular DNA at an origin of replication and replicating bi-directionally to form a theta-shaped structure.
4. Bidirectional replication of linear DNA involves unwinding DNA at origins of replication and using leading and lagging strand synthesis to replicate in both directions until the ends of the linear genome are reached.Similar to Cyclin dependent kinases (20)
Cdk
CdkSuba Venkat
油
Cyclin dependent kinases (CDKs) play a key regulatory role in controlling the cell cycle. CDKs form complexes with cyclins and their activity varies throughout the cell cycle. There are checkpoints that ensure DNA replication and division occur accurately. CDK-cyclin complexes promote progression through the cell cycle phases (G1, S, G2, M) by phosphorylating target proteins. Cyclin levels oscillate while CDKs are constantly present. Together they activate enzymes and proteins required for DNA replication and mitosis. Precise regulation of CDK-cyclin complexes and degradation of cyclins through ubiquitination is crucial for orderly cell cycle progression.Cell Cycle_ Usman.pptx sasgdgdb vdf g g rg g
Cell Cycle_ Usman.pptx sasgdgdb vdf g g rg gmunshi5
油
The cell cycle is regulated by cyclins, cyclin-dependent kinases (CDKs), and tumor suppressors. The M phase is the shortest phase and includes mitosis and cytokinesis. G1 phase duration is variable. CDKs must bind to cyclins to transition between phases and are inhibited by CDK inhibitors in the presence of errors. The Cyclin D/Cdk4 complex initiates DNA replication by phosphorylating the retinoblastoma protein (pRb). The p53 tumor suppressor inhibits DNA replication through activating pRb and initiating apoptosis in cells with irreparable DNA damage.CELL DIVISION AND ITS REGULATION.pdf
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油
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油
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Thankyou.cell cycle
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Cell Cycle and Dna replication.pdf very goodunspokenbuddy
油
The document summarizes the key phases and checkpoints of the cell cycle, as well as the roles of cyclins and cyclin-dependent kinases (CDKs) in regulating progression through the cell cycle. It notes that the cell cycle consists of M (mitosis), G1, S (DNA synthesis), and G2 phases, with checkpoints to detect errors and damage. Cyclins activate CDKs to phosphorylate proteins and drive progression, with Cyclin D activating CDK4/6 to promote G1/S transition, Cyclin E and A activating CDK2 to initiate DNA synthesis, and Cyclin B activating CDK1 for G2/M transition. The Rb protein also regulates the G1 checkpoint
Cell cycle regulation 17 bcb0016
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This presentation on "Cell Cycle regulation" takes you to the cell cycle describing the stages and checkpoints involved providing some of the evidences of cell cycle regulation. Then we will move to cyclins and cyclin dependent kinases and the mechanism they follow.
This journey in regulation of cell cycle will take a halt after a general discussion of positive and negative cell cycle regulators.
Thankyou.New Microsoft Office PowerPoint Presentation-1.pptx
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The cell cycle is a precisely programmed series of events that enables a cell to duplicate its contents and divide into two daughter cells. It consists of interphase (G1, S, G2 phases) and mitosis (M phase). Progression through the cell cycle is regulated by cyclins and cyclin-dependent kinases (CDKs). CDK activity is controlled by association with cyclins, CDK inhibitors, and phosphorylation. Checkpoint pathways like the G1/S, G2, and spindle assembly checkpoints ensure replication and division errors are corrected before progression. Deregulation of these checkpoint pathways can lead to genomic instability and carcinogenesis.Cell cycle regulation
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This slideshow contains various stages of cell cycle regulation, cell cycle checkpoints and their proteins involved in regulation. Cell cycle checkpoints transition phases.Cell cycle checkpoints, apoptosis and cancer
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1. The document discusses various aspects of the cell cycle, including its key phases and regulating molecules. It notes that the cell cycle includes growth, DNA replication, chromosome separation, and cytokinesis.
2. Major regulatory molecules discussed include cyclins, CDKs, Rb protein, and checkpoints like START that ensure DNA damage is repaired before progression.
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The cell cycle is tightly regulated by both positive and negative regulators to ensure accurate DNA replication and cell division. Positive regulators like cyclins and cyclin-dependent kinases (CDKs) control progression through the cell cycle phases. Negative regulators including the retinoblastoma (Rb) protein and p53 protein oppose cell cycle progression in response to DNA damage or other problems. Checkpoints at the G1/S and G2/M transitions verify DNA integrity before allowing the cell to progress further. Faulty regulation of these cell cycle controllers can lead to uncontrolled cell division and cancer.Cell cycle and tumor kinetics
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- The cell cycle consists of four main phases - G1, S, G2, and M. The G1, S, and G2 phases make up interphase.
- The cell cycle is tightly regulated by cyclins and cyclin-dependent kinases (CDKs). Different cyclin-CDK complexes control progression through the different cell cycle phases.
- Checkpoints exist to monitor DNA damage before progression into S phase and M phase. These checkpoints are regulated by proteins like ATM, ATR, Chk1, Chk2, and p53.
- Dysregulation of cell cycle control and checkpoint pathways contributes to uncontrolled cell proliferation in cancer. Both oncogenes and tumorCell Cycle, Cell cycle Check Points, Cell cycle regulation and Tumor Suppress...
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An overview on Cell Cycle and CancerCELL SIGNALLING.pptx
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The phenomenon of signal transduction, also known as cell signaling, pertains to the intricate mechanisms that facilitate the transfer of biological information between cells. The effective coordination of diverse specialized cell types in various tissues and organs is a prerequisite for the proper functioning of complex multicellular organisms, necessitating intercellular communication. This communication must be continuous and dynamic to maintain coordination. Additionally, cell signaling pathways play a crucial role in the mechanisms of action of numerous drugs, including both local and general anesthetics. Consequently, a fundamental understanding of cell signaling mechanisms is imperative for comprehending various pathophysiologic and pharmacologic mechanisms.Cyclin-Dependent Kinase
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Cyclin-dependent kinases (CDKs) belong to a protein serine/threonine kinases whose activity depends on association with a noncatalytic regulatory subunit called a cyclin. Cyclin-dependent kinases inhibitors are vital for progression through the cell cycle and proliferation. Cell cycle and its regulation
Cell cycle and its regulationpriyanshugupta1515
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The cell cycle is regulated by cyclin-dependent kinases (Cdks) whose activity oscillates throughout the cycle. Cdks form complexes with cyclins, which activate the Cdks and determine which phase of the cycle they control. The cyclin-Cdk complexes phosphorylate target proteins to promote replication and mitosis. Progression through the cell cycle is also controlled by ubiquitin ligases and phosphorylation/dephosphorylation events. The cycle operates through a series of switches that trigger irreversible events, keeping it tightly regulated and coordinated.Cell cycle regulation Basics
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The cell cycle is the ordered series of events that leads to cell division into two daughter cells. It consists of four main phases: G1, S, G2, and M. Checkpoints ensure each step is completed before progression. Cyclins activate CDKs at specific phases - G1 cyclins activate G1 CDKs which promote DNA replication by phosphorylating Rb and activating E2Fs. S-phase CDKs activate DNA replication origins. Mitotic CDKs promote mitotic events like spindle formation and chromosome condensation. Completion of mitosis involves chromosome segregation and cyclin degradation to inactivate CDKs and allow cell division.Please answer all of #5 After the completion of S phase, F.2F functi.pdf
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Phosphorylation by Wee1 regulates cyclin/CDK activity by inhibiting Cdk1 through
phosphorylation. Dephosphorylation by Cdc25 activates cyclin/CDK activity by removing
inhibitory phosphates from Cdks. Binding by cyclin dependent kinase inhibitors (CKIs) regulates
cyclin/CDK activity by interacting with cyclin-CDK complexes to block their kinase activity.
Degradation of cyclins by the proteasome regulates cyclin/CDK activity by using proteasomes to
degrade cyclins after they have performed their function, providing directionality to the cell cycle.cell cycle 1st sem.pptx
cell cycle 1st sem.pptxdikshasingh649964
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The document summarizes the cell cycle and its regulation. It discusses the main phases of the cell cycle including interphase (G1, S, G2 phases) and the M phase. It also describes key cell cycle checkpoints and the proteins involved in regulating progression through the cycle, such as cyclins, CDKs, and CDK inhibitors. Precise control of the cell cycle is essential as any errors could lead to cancer.Cell Cycle, Cell cycle Check Points, Cell cycle regulation and Tumor Suppress...
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Cyclin dependent kinases
- 2. What are CDKs? Cyclin-dependent kinases (CDKs) are protein kinases involved in critical cellular processes. They are important in the regulation and control of cell cycle. They are also involved in regulating transcription, mRNA processing, and the differentiation of nerve cells. They are always present in the cells in their inactive form , but the binding of a cyclin activates it, making it a functional enzyme and allowing it to modify target proteins. CDKs are the enzymes that phosphorylates specific target proteins and the attached phosphate group acts like a switch, making the target protein more or less active.
- 3. Checkpoints of cell cycle:
- 4. Cyclin and CDK complexes present in different phases :
- 9. Tumor suppressor protein retinoblastoma (Rb) protein holding transcription factor E2F. cyclin_-CDK complex phosphorylate the Rb protein and leads the release of E2F. E2F can then activate transcription of the cyclin E gene. Cyclin E binds CDK2, and this complex fully phosphorylates Rb, completing its inactivation. Cyclin E also phosphorylates p27Kip1, an inhibitor of Cyclin D. Phosphorylation of p27Kip1 tags it for degradation. Degradation of this protein promotes expression of cyclin A. During S phase, Cyclin A ensures that DNA replication only occurs ONCE per cell cycle by preventing assembly of excessive replication complexes.
- 10. The Cyclin A-CDK2 complex also regulates DNA replication by phosphorylating certain DNA replication machinery components. When the cell transition occur to M phase cyclin A gets replaced with cyclin B. Cyclin B is a mitotic cyclin which binds to CDK1 to form the maturation promoting factor, or mitosis promoting factor . The concentration of MPF rises until mitosis, until its concentration falls abruptly due to degradation of Cyclin B. High concentrations of Cyclin B are necessary for cells to enter M phase, and low concentrations are needed to exit M phase.
- 11. When DNA damage is their cyclin cdk inhibitors gets activated i.e. Tumor suppressor proteins like p53,p21,p27kip1 etc. P53 activates p21 and binds all cyclin cdk complexes and activity of Rb proteins get restored and E2F is inactivated . Transcription gets halt and cell gets time for the repair of DNA damage.
- 14. References : https://youtu.be/VLJF8Pf8spw https://youtu.be/nEMMKzYQf9A Nelson and Cox Lehninger principles of biochemistry 6th edition (chapter no.12) https://www.khanacademy.org/science/ap-biology/cell- communication-and-cell-cycle/regulation-of-cell-cycle/a/cell- cycle-regulators
- 15. Thank you!