Course Hero Logo

O binds and stops the complex the degradation of its

Course Hero uses AI to attempt to automatically extract content from documents to surface to you and others so you can study better, e.g., in search results, to enrich docs, and more. This preview shows page 46 - 49 out of 73 pages.

oBinds and stops the complexThe degradation of its cyclin partner by ubiquitination.oUbiquitin proteins can bind to cycling proteins and causes the degradation of cyclingproteinsRole of p53 and Retinoblastoma ProteinsRb Protein & Regulation of Cell CycleRb Protein = Retinoblastoma proteinsoUsually inactive because it has a phosphateoWhen phosphate is removed it becomes activeStepsoDamaged DNA triggers dephosphorylation of Rb protein.Damaged DNA means phosphate is removed from Rb proteinWe now have an active Rb proteinoDephosphorylated Rb binds to TEE and prevents transcription of G1/S transitioncyclin/CDK genes.Active Rb protein binds to transcription enhancer elements (TEE)This stops G1S Transition genes46
PhysiologyExam 1The genes don’t get transcribedoStops cell cycle progression for damaged cell.oMutations in Rb protein led to the retinoblastoma.This is a form of cancerp53 & Regulation of Cell CycleStepsoDNA damageoproductions of p53Leads to 2 things when the cell cycle arrestDamage is repairablecell cycle restartDamage is unrepairableapoptosisIf p53 is mutated these functions cannot be done and we have cancerApoptosis and CaspasesWhy Should a Cell Commit Suicide?Apoptosis is needed for proper developmentoThe formation of the fingers & toes of the fetusoThe sloughing off the endometrium (menstruation)Apoptosis is needed to destroy harmful cellsoCells infected with viruses & intra-cellular pathogens.oSelf-reacting immune cells.oImmune cells at the end of their battle.oMutated cells, aged cells, dead cells.oTransformed cells and Cancer cells.CaspasesSuicide proteases (enzymes)oCaspases are a family of genes important for maintaining homeostasis through regulatingcell death and inflammation.oExist in all cells asprocaspases(inactive).oProcaspases are activated by either extracellular or intracellular death signals.They go from being procaspases (inactive) to caspases (active)oAre critical for transduction of death signals.Type of CaspasesInitiator CaspasesoCaspase 2, 8, 9 and 1047
PhysiologyExam 1oInitiate the apoptosis signal.Executioner CaspasesoCaspase 3, 6 and 7oCarry out the mass proteolysis that leads to apoptosis.Carry out DNA degradation and completing apoptosisInflammatory CaspasesoCaspase 1, 4, 5, 11 and 12oDo not function in apoptosis.Different Pathways of Cell ApoptosisMechanisms of ApoptosisExtrinsicoDeath signals or Death ligands are tumor necrosis factor (TNF) and factor of apoptosissignal (Fas)Bind with death receptoractivate caspase 8caspase 3 activatesprocess of degradation of DNA & cellsIntrinsicoDeath signals are Radiation, toxins, hypoxia, etc.cause mitochondrial changes &formation of apoptosomecaspase 9 activationcaspase 3 activationprocess ofdegradation of DNA & cellsGranzymeoT cytotoxic cells, / t lymphocyte (immune cells) produce perforin proteinstheseproteins cause a pause in the cell membranethe pause allows injection of granzyme Bcaspase 10 activationcaspase 3 activationprocess of degradation of DNA & cellsRole of Mitochondria in ApoptosisMitochondrial PathwayAnti-apoptoticoBcl-2 family members block mitochondrial cytochrome C release.

Upload your study docs or become a

Course Hero member to access this document

Upload your study docs or become a

Course Hero member to access this document

End of preview. Want to read all 73 pages?

Upload your study docs or become a

Course Hero member to access this document

Term
Summer
Professor
NoProfessor
Tags
DNA, Homeostasis

Newly uploaded documents

Show More

Newly uploaded documents

Show More

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture