[livetolaugh]

Our TA told us what one of the questions on my mid-term was gonna be, and I have no idea how to solve this. Any help is very much appreciated TY! Hopefully 2p2 saves the day again haha.


A graduate student you know is researching a cell line obtained from Xenopus embryos that, at 21C, proliferate and differentiate into cardiomyoctes. The signaling system leading to differentiation seems to involve the PI3K-Akt/PKB signaling module. On Oct 31st, the grad student placed his cells in the lab’s incubator not realizing that a 4th year honors thesis student, whose research involves temperature sensitive GEFs in this poikolothermic organism, had increased the temperature to 35C. The next day, after a night of tricks/treats, the graduate student discovered that his cells were producing an autocrine factor that was causing the cells to proliferate without differentiating and were capable of record rates of motility. The graduate student, for obvious reasons, named the factor SCARY (XSC). The 4th year student offered to determine the effects of XSC at 21C which allowed her to demonstrate that the cells responded at the lower temperature by differentiating into cardiomyocytes. Hence, both students benefited from the accident!

You feel you are in a position to help the students in the lab. Suggest to them the signaling pathways that could explain the above results (30 marks) and suggest experimental approaches that could be used to test the veracity of the hypothesized pathways (20 marks).