according to the competence-progression model , regulation of cell proliferation occurs at two sites : 1 ) the g0 to g1 transition , where competence factors ( e.g. , platelet-derived growth factor [ pdgf ] and interleukin 1 [ il-1 ] ) act , and 2 ) during g1-phase , where progression factors ( e.g. , interleukin 2 [ il-2 ] and il-3 ) act .
C1156235
regulation of cell proliferation
C0021756
interleukin 2