7.2 Matching: indicate whether the following receptors are receptor tyrosine kinases (RTKs), are receptor serine/ threonine kinases (RSTKs), or have no intrinsic enzymatic activity (null).
A. ___ Kit
B. ___ B-cell receptor C. ___ fLT3
D. ___ TGf-β receptor 7.3 Short Answer: how can scaffolds and adaptors modulate signaling responses if they have no intrinsic enzymatic activity?
7.4 Multiple Choice: Which of the following alterations would result in increased activity of Ras (one or more may apply):
A. a mutation in Ras that enhances its GTpase activity
B. overexpression of Gefs
C. depletion of GTp in the cytoplasm
D. overexpression of Gaps
E. a mutation in Ras that renders it unsusceptible to the activities of Gaps 7.5 Matching: order (by numbering 1–5) the downstream signaling events that occur immediately after T-cell receptor engagement: ____ LaT and SLp-76, scaffold proteins linked by Gads, are phosphorylated ____ Zap-70, a tandem Sh2 domain containing kinase, binds to iTams ____ Recruitment and activation of Sh2, ph, and pX domain-containing proteins ____ pi 3-kinase is activated and produces pip3 ____ phosphorylation of iTams by Lck, a Src-family kinase 7.6 Fill-in-the-Blanks: for each of the following sentences, fill in the blanks with the best word selected from the list below. each word should be used only once.
LaT:Gads:SLp-76 akt antigen receptor signaling leads to many downstream events that branch out into many signaling pathways or modules. These can be activated by the scaffold complex ___________, the generation of pip3 from pip2 by the enzyme ____________, or both. phosphorylated tyrosine residues on the scaffold recruit proteins containing ___________ domains, while pip3 recruits proteins containing ___________ domains. These four modules are the activation of (1) ___________, which cleaves pip2 to produce daG and ip3, (2) ___________, which binds to pip3 and activates the mToR pathway by phosphorylating and inactivating the TSc complex, (3) ____________, an adaptor that recruits SKap55 and Riam, and (4) __________, a Gef that leads to activation of WaSp. These pathways ultimately lead to increased transcription of key genes, increased cellular metabolism, increased cellular adhesion, and actin polymerization, respectively.
7.7 Matching: match the small G protein (GTpase) to its function.
A. _____ Ras i. WaSp; actin polymerization
B. _____ cdc42  ii. mToR; cellular metabolism (Rho family)
C. _____ Rap1 iii. Lfa-1 aggregation; cellular adhesion
D. _____ Rheb iv. mapK pathway;  cellular proliferation 7.8 Multiple Choice: Which of the follow statements is false?
A. K63 polyubiquitination leads to downstream cellular signaling.
B. K48 polyubiquitination leads to degradation by the proteasome.
C. out of the three families of enzymes involved in ubiquitination—e1 (ubiquitin-activating) enzymes, e2 (ubiquitin-conjugating) enzymes, and e3 enzymes (ubiquitin ligases)—cbl is an e3 enzyme that selects its target via its Sh2 domain.
D. monoor di-ubiquitination of surface receptors leads to degradation by the proteasome.
7.9 Matching: match the human disease with the gene that is
D. ____ X-linked hypohidrotic iv. WaSp ectodermal dysplasia and immunodeficiency 7.10 Fill-in-the-Blanks: name the corresponding receptor or signaling component in its respective T/B cell counterpart: