Gene Activity

Question 1

What are the steps of the Jak stat pathway?

Answer 1

Interferon binds the receptor, JAK cross phosphorylate each other, Activated JAKs phosphorylate receptors on tyrosines, STATs dock on phosphotyrosines and are phosphorylate by JAK, STAT dissociates fro receptor and dimerize via their SH2 domains, STATs migrate to nucleus, bind to DNA and other gene regulatory proteins

Question 2

JAK

Answer 2

tyrosine kinase which binds the ligand-bound cytokine receptor

Question 3

STAT

Answer 3

transcription factor which is phosphorylated by JAK

Question 4

Cytokines

Answer 4

local mediator of growth and cell division

Question 5

What are two examples of cytokines?

Answer 5

interferon, growth hormone

Question 6

TGF beta receptors

Answer 6

serine/threonine kinase receptors that prevent cell division

Question 7

How are TGF beta formed?

Answer 7

cleavage of a secreted inactive precursor

Question 8

What polypetptides make up TGF beta receptors?

Answer 8

RI, RII and RIII

Question 9

How is TGF beta activated?

Answer 9

RII binds to TGF beta and induces complex formation with RI, and phosphorylation and activation of RI kinase

Question 10

What happens after the TGF beta receptor is activated?

Answer 10

Smad 2 or 3 binds to the receptor and becomes phosphorylated then dissociates from receptor and oligomerizes with smad 4 then migrates to the nucleus and recruits gene regulatory proteins and activates transcription of specific target genes