Discussion of all aspects of cellular structure, physiology and communication.
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Im so annoyed. I was researching the answer to your question and tried to open a PDF about the cell cycle and wee1 and firefox crashed. And i lost everything i'd typed for the reply. I love firefox but it doesnt like large PDFs.
From what i'd found CDC25 can be phosphorylated on several serine residues. 5 if i remember correctly. It has been shown that CDC25C is highly phosphorylated at the G2-to-M transition and has five serine/threonine-proline sites: Thr48, Thr67, Ser122, Thr130, and Ser214. From here:http://ajpcell.physiology.org/cgi/content/full/284/2/C349#B32
also From here: http://www.sciencemag.org/cgi/content/a ... f_ipsecsha
results indicate that serine-216 phosphorylation and 14-3-3 binding negatively regulate Cdc25C and identify Cdc25C as a potential target of checkpoint control in human cells.
I'll have a look at the rest of the questions later, (i need to get back to work),
OK. FOUND SOMETHING .WHENS YOUR HOMEWORK DUE IN?
Its amazing what google finds.
This is incredible. You have the answers on the web: http://www.msu.edu/course/mmg/409/hw11a.pdf
Ok. the questions are slightly different. Your first question is identical to the previous ones.
2) Okadaic acid question - This helps " Okadaic acid has no effect on Cdc2 phosphorylation because it is phosphorylated on a tyrosine residue. Tyrosine phosphatases are unaffected by okadaic acid. The decrease in Cdc2 phosphorylation is a consequence of the change in activation of Wee1 kinase and Cdc25 phosphatase." And this "Why does Okadaic acid cause an increase in Phosphorylation of Wee 1 and Cdc25 and
a decrease in P of Cdc 2?
Phosphate on Cdc 2 is on tyrosine. Because odadaic acid causesCdc25 to be
active, this causes a removal of the inhibitory tyrosine phosphate and Cdc2 runs faster on
the gel." CDC2 is cdk1. (yeast/mammalian).
3) Final question: Bit tricky: MPF activates cdc25 and inhibits wee1. active cdk would phosphorylate cdc25 and wee1. WAIT. Is this your homework:http://www.msu.edu/course/mmg/409/hw11.pdf
the last question says "Can you explain how the appearance of a small amount of active MPF" NOT ACTIVE CDK! Active MPF would make a lot more sense. Im really confused now. You'll have to get back to me on all that.
Note for question 2) Okadaic acid is an inhibitor of serine/threonine protein phosphatases. it is specific for serine/threonine phosphatases. Thats why it causes an increase in phosphorylation of wee1 and cdc25 as its specific for these serine/threonine phosphatases. DO YOU NEED EXPLAIN WHY ITS SPECIFIC? That could involve some tricky biochemistry.
The decrease in phosphorylation of cdk is quote "The decrease in Cdc2 phosphorylation is a consequence of the change in activation of Wee1 kinase and Cdc25 phosphatase."
Hope thats a bit clearier. ?
Your going to have to put all this in your own words as your teacher will know the past answers are on the web.
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