October 26, 2010 at 11:18 am #14011
On a recent test, this question appeared and I was really sure I had the right answer… Only I didn’t. Now I really don’t get the question and I would like to ask you to help me! This is the question:
The growth factor Superchick stimulates proliferation of cultured chicken cells. The receptor that binds Superchick is a receptor tyrosine kinase, and many tumor cell lines have mutations in the gene that encodes this receptor.
Which of the following types of mutations would be expected to induce uncontrolled cell proliferation? (2 points):
a) A mutation that prevents localization of the receptor to the plasma membrane.
b) A mutation that prevents dimerization of the receptor.
c) A mutation that destroys the kinase activity of the receptor.
d) A mutation that prevents recognition of the receptor by phosphatases.
e) A mutation that prevents ligand binding.
I won’t post my answer and explanation yet, so you can form your own answer and maybe help me understand! 🙂
October 26, 2010 at 1:39 pm #101998canalonParticipant
October 26, 2010 at 7:09 pm #102001
Thank you! Could you please also explain why?
October 26, 2010 at 9:13 pm #102002canalonParticipant
From my distant memories of regulation of kinase cascades, that looks like the more logical response. Now I could probably elaborate more, but only after you tell me what was your answer and how you came to it.
Oh and by the way, I would take my answer with a grain of salt…
October 27, 2010 at 12:06 pm #102009
I thought D as well, because the phosphatases inactivate an active receptor tyrosine kinase by plucking of the phosphategroups, and if the phosphatases cannot recognize the receptor tyrosine kinase anymore it will remain active and keep on stimulating cell proliferation.. Right?
But that’s wrong, because it’s supposed to be A… Do you have any possible explanation for that answer? I really don’t.
Thanks by the way.
October 28, 2010 at 2:37 pm #102028JackBeanParticipant
I would guess d as well.
Question is, where should it be localised elsewhere? Maybe the mislocalisation would cause loss of dephosphorylation process. However, the kinase activity shouldn’t be activated either.
October 30, 2010 at 9:23 am #102068
Yes, thank you. I think the teacher just made a mistake then. When, and if, I get a response from him I’ll let you know!
Thanks for all your help, canalon and JackBean 🙂
You must be logged in to reply to this topic.