true or false? And why it is false For the actin cytoskeleton, diverse cell-surface receptors trigger global structural rearrangements in response to external signals. But all these signals seem to converge inside the cell on a group of closely related monomeric GTPases that are members of the Rho protein family—Cdc42, Ras, and Rho. The same Rho family proteins are also involved in the establishment of many kinds of cell polarity

true or false? And why it is false For the actin cytoskeleton, diverse cell-surface receptors trigger global structural rearrangements in response to external signals. But all these signals seem to converge inside the cell on a group of closely related monomeric GTPases that are members of the Rho protein family—Cdc42, Ras, and Rho. The same Rho family proteins are also involved in the establishment of many kinds of cell polarity

Biology 2e

2nd Edition

ISBN:9781947172517

Author:Matthew Douglas, Jung Choi, Mary Ann Clark

Publisher:Matthew Douglas, Jung Choi, Mary Ann Clark

Chapter9: Cell Communication

Section: Chapter Questions

Problem 1VCQ: Figure 9.8 HER2 is a receptor tyrosine kinase. In 30 percent of human breast cancers, HER2 is...

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GTP binding proteins are molecular switches. How do GTP binding proteins work? Provide two examples of GTP binding proteins that function in intracellular protein transport. Make a drawing that illustrates the function of each of these proteins in their respective roles. Predict the direct outcome of a mutation that: Inhibits GTPase activity Inhibits interaction with the GEF
TGF-B Receptor I (RI) phosphorylation of Smad2/3 does all of the following EXCEPT: activate Smad2/3 binding to the Co-Smad Smad4 dissociate intramolecular binding of Smad2/3 MH1 and MH2 domains. RI phosphorylation of Smad2/3 does all of these things. release Smad2/3 from the nucleus into the cytoplasm unmask the Smad2/3 nuclear localization signal (NLS).
Cyclin-dependent kinases are a type of "microchip" protein that require multiple inputs (i.e., structural alterations) to be activated-- and thus are active only under specific conditions (as shown in the diagram below). How does limiting activity to when all conditions have been met help the cell function properly? INPUTS has this phosphate been removed? been added? has this is cyclin present? phosphate
"given the numerous processes inside cells that are regulated by changes in Ca+2 concentration, it seems likely that Ca¹²-dependent cell-cell adhesions are also regulated by changes in Ca2 concentration" is true or false.
# 3 You've engineered a mutant cell where the FADD adapter was truncated. The mutant FADD only contains the Death Domain, and lacks the Death Effector Domain. What is the most likely phenotypic outcome for this mutant cell when presented with the Fas ligand? 20 E O The Fas/FasL oligomer is formed, but apoptosis is blocked O The Fas/FasL oligomer is formed, and apoptosis is hyperactivated O The Fas/FasL oligomer is not formed, and apoptosis is blocked O The Fas/FasL oligomer is not formed, but apoptosis is hyperactivated F3 $ 4 DOD 000 R F4 % 5 F5 T BARAT 6 tv @ MacBook Air F6 Y & 7 F7 U * ➤11 8 F8 · 9 F9
Receptor tyrosine kinases such as the epidermal growth factor (EGF) receptor can basically be broken down into three domains: (1) An extracellular, ligand binding domain, (2) A transmembrane domain that must cross through the cell membrane, and (3) an intracellular domain. Match the amino acid with the domain that it would MOST LIKELY be associated with. Lysine (choose (1), (2), or (3) from above) A tyrosine residue capable of being phosphorylated on its hydroxyl group (choose (1), (2), or (3) from above) Isoleucine (choose (1), (2), or (3) from above)
Cytokine receptors and tyrosine kinase receptors are similar in all of the following ways EXCEPT one. Which one is the exception? O They are both down-regulated by lysosomal degradation They both involve receptor exoplasmic domain dimerization They both result in an effector protein entering the nucleus O They both involve cytosolic domain phosphorylation
The affinity of integrins for matrix components canbe modulated by changes to their cytoplasmic domains:a process known as inside-out signaling. You have iden-tified a key region in the cytoplasmic domains of αIIbβ3integrin that seems to be required for inside-out signaling(Figure Q19–3). Substitution of alanine for either D723in the β chain or R995 in the α chain leads to a high levelof spontaneous activation, under conditions where thewild-type chains are inactive. Your advisor suggests thatyou convert the aspartate in the β chain to an arginine(D723R) and the arginine in the α chain to an aspartate(R995D). You compare all three α chains (R995, R995A,and R995D) against all three β chains (D723, D723A, andD723R). You find that all pairs have a high level of sponta-neous activation, except D723 vs R995 (the wild type) andD723R vs R995D, which have low levels. Based on theseresults, how do you think the αIIbβ3 integrin is held in itsinactive state?
Working out the order in which the individual components in a signaling pathway act is an essential step in defining the pathway. Imagine that two protein kinases, PK1 and PK2, act sequentially in a kinase cascade. When either kinase is completely inactivated, cells do not respond to the normal extracellular signal. By contrast, cells containing a mutant form of PK1 that is permanently active respond even in the absence of an extracellular signal. Double mutant cells that contain inactivated PK2 and permanently active PK1 respond in the absence of a signal. Draw out the signaling pathway in a wild-type cell. What outcome is predicted for a double mutant cell with an activating mutation in PK2 and an inactivating mutation in PK1? Explain your reasoning
Figure 9.8 HER2 is a receptor tyrosine kinase. In 30 percent of human breast cancers, HER2 is permanently activated, resulting in unregulated cell division. Lapatinib, a drug used to treat breast cancer, inhibits HER2 receptor tyrosine kinase autophosphorylation (the process by which the receptor adds phosphates onto itself), thus reducing tumor growth by 50 percent. Besides autophosphorylation, which of the following steps would be inhibited by Lapatinib? Signaling molecule binding, dimerization, and the downstream cellular response. Dimerization, and the downstream cellular response. The downstream cellular response. Phosphatase activity, dimerization, and the downsteam cellular response.
I just read an abstract of the paper “Disulfide bond-disrupting agents activate the tumor necrosis family-related apoptosis-inducing ligand/death receptor 5 pathway” and noted that “DDAs and TRAIL synergize to kill cancer cells and are cytotoxic to HER2+ cancer cells with acquired resistance to the EGFR/HER2 tyrosine kinase inhibitor Lapatinib.” For the last sentence, I am not sure the meaning of the “acquired resistance to the EGFR/HER2 tyrosine kinase inhibitor Lapatinib”. Is the “acquired resistance ... to inhibitor” a good thing or bad thing, as far as the synergize effect of DDAs and TRAIL”? Hope that expert can help.
Cell signaling in plant and animal cells is similar in some ways and different in others. Offer one or more hypotheses for these similarities and differences,and cite specific examples.