Question

Differentiate between the normal cellular actions / functions of a tumor suppressor and a protooncogene. Using p53 and Ras as specific examples, describe one of the pathways each are involved in (can be a specific pathway or a more general type of pathway). Explain what type of mutation, for each protein, would lead to disruption of the pathway. Finally, explain how disruption of this pathway could lead to cancer. You can use the chart below to answer the question tumor suppressor p53 protooncogene Ras functions pathway type of mutation consequence of disruption of the pathway

Answer 1

One lons . ALSO Tumor suppressor_p53/_ pustooncogene_Ras Bas_pooleins are roonomerve Iisa transcuibtion regulatory GTPases which are involved in protein that is activated by transmiting signalp_form prevents - damage to DNA or telomere shofening cell suo face receploss to the - toon Is involved in blocking fwither cell interiori cancer by inhibiting progression through cell cycle.tl Actoralēz mTOR pathway to puoliferation It also induces apobtosis. stimulaté cell growth It is also a cellular Stress Bensor. Activaled by a cyclic AMP.-- pathway dependent GEFE inficence adhesion. P53 acts through various pathways like apoptosis "Ras activates a Map kinase mediated ete. Parthur ago consequence of disruplūon of excessive taponto main mutations are in Ras oncogones contains point mutationen - DNA binding domain, where mutation that create by pero pathway they cripple the ability of p53 | Ctive Ras protein that cannot to bind to its DNA target Shut itself from hydrolysing sequence. Hence ultimate its bound GTP & GOP. THIS konsequence leads to delle results in constitutive activation pevotiferation and cancer. of Ras which causes cancer Type of mutation : Single missense por point mutation in dosequence mutations are generally Ras oncogene Bumayed withfound in 1P53 gene. The Bonner
p53 pathway
X-rays DNA DNA damage ATM/ATR kinase activation Chk1/Chk2 kinase activation Mdm2 PHOSPHORYLATION OF p53 stable, active p53 p53 p53 UBIQUITYLATION AND DEGRADATION IN PROTEASOMES ACTIVE p53 BINDS TO REGULATORY REGION OF p21 GENE p21 gene TRANSCRIPTION p21 mRNA TRANSLATION p21 (Cdk inhibitor protein) WW ACTIVE G1/S-Cdk and S-Cdk INACTIVE G/S-Cdk and S-Cdk complexed with p21 Scanned with CamScanner
ras pathway

inactive Ras protein active Ras protein GDP GDP W GTP F P 111 GTP SH3 SH3 Ras-GEF (Sos) DOWNSTREAM SIGNALS PSH2 adaptor protein (Grb2) activated RTK Scanned with CamScanner