C H A P T E R Mitogenic Signal Transduction •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• Th • abilit to s 'ns ' .md respond to 'n\"iron- m 'ntal signals is fundam 'ntal 10 Ih' cl'v 1- Opl11 nl ami sur\'i\'al of all organisms. At the lIular le\' I, t ·rn.,1 u s 'u h as t mp 'ra- ture, osmotic pre' 'ur, pr" nc' or ab' 'ne of nutri nts, and prescncc or abs ncc of spe- eifi hormone ... ur growth faetm ... ar' ontinu- ousl m( nit red. Thc pr ... s of p r iving and responding to su h signals i t rm Li sig- nal transdu tion. Hü hapt 'r pr \'id an \' f\'iew of sig- nal transdllction mcchani. ms that affcct ceU prolif 'ration and morph log. This ehapt 'r r uses on mammalian IIs, b all"e ontn I of signaling is r I 'vant tu thc path( gen ( f human malignan j s; lu W'\'l!r, it .,h lU/cl b not that U, ,I 'm nts of man signaling pathwa s are highl conscrved in alt clIkary- 01 s. Th· high d 'gr • Jf con '.-vatinn among signaling pathwa s has mild g n ti ally Ira t.,bl) mod -I organi ms such as y >ast, fruH fli s, and f(lllndwurms \'aluabl' I< ols in d ,t 'rmining th organ;i'<,ti n of ignaling t '111 in humans. ign.,l Iransduction entails Ihc r 'ption ami tran mi. sion of n\'ir nm I1tal u , n: ulting in approprial' bi lugic r 'sponSt: . Jonathan Chernoff G. D. Kruh et al. (eds.), Basic Science of Cancer © Current Medicine, Inc. 2000