The activation of p70(s6k) is accompanied by a complex series of phosp
horylation events. In this review we propose a model of activation whi
ch divides p70(s6k) into four functional modules that cooperate in lea
ding to full enzyme activity. In the light of the model, we suggest ho
w candidate effectors of p70(s6k) activation might function by directi
ng the phosphorylation of specific sites. (C) 1997 Federation of Europ
ean Biochemical Societies.