[thedoc (OP)]

Adam asked the Naked Scientists:
   hi I am just revising for my cancer biology module and have noticed that G proteins use GTP in cell signalling (e.g. Ras etc) and a question occurred to me.

How come cells use that GTP rather than ATP in cell signalling?  I know this is a bit of a specific question for the show, but I just thought I'd quiz you guys to see if you knew.

It's coming up to my fourth year of subscribing to the podcast now and haven't missed one yet, keep up the good work guys.

Adam :-)
What do you think?