#Question id: 15489
#Unit 12. Applied Biology
#Question id: 1187
#Unit 4. Cell Communication and Cell Signaling
Which protein stabilizes an intermediate in the Ras GTP hydrolysis reactions?
#Question id: 23677
#Unit 13. Methods in Biology
#Question id: 23146
#Unit 13. Methods in Biology
#Question id: 1251
#Unit 4. Cell Communication and Cell Signaling
Following statements are regarding to receptor serine kinases.
A. The two serines in each Smad3 that were phosphorylated by the RI receptor kinase bind to phosphoserine-binding sites in the MH1 domains of a Smad3 or a Smad4, forming a stable complex containing two molecules of phosphorylated Smad3 (or Smad2) and one molecule of the co-Smad (Smad4).
B. The bound importin then mediates translocation of the heteromeric R-Smad/co-Smad complex into the nucleus.
C. After importin dissociates inside the nucleus, the Smad3/Smad4 (or Smad2/Smad4) complex binds to other transcription factors to activate transcription of specific target genes.
D. Transcription of the PAI-1 gene requires formation of a complex of the transcription factor TFE3 with the R-Smad/co-Smad (Smad3/Smad4) complex and binding of all these proteins to specific sequences within the regulatory region of the PAI-1 gene.
E. Within the nucleus, R-Smads are further modified by phosphorylation of their linker domains, monoubiquitinylation of their MH1 domains, acetylation of their MH2 domains, and dephosphorylation of the C-terminal serines by nuclear phosphatases.
Which of the following combination is incorrect?