The phosphatidylinositol 3-kinase alpha is required for DNA synthesis induced by some, but not all, growth factors.

• DOI: 10.1073/pnas.91.19.9185
• Publication Date: 2006-05-31T12:55:18Z
• Authors: S Roche; M Koegl; S A Courtneidge
• Keywords: Platelet-derived growth factor

The phosphatidylinositol 3-kinase (PI 3-K) becomes activated when quiescent cells are stimulated with a variety of growth factors. We have microinjected antibodies specific for the p110 alpha subunit PI 3-K into fibroblasts and tested their effect on ability factors to stimulate exit from quiescence entry S phase. inhibited platelet-derived factor-induced DNA synthesis, result in keeping previous studies using mutant factor receptors. Interestingly, functional was required first 6 hr G1--i.e., until approximately 4 before point at which were committed make DNA. A second tyrosine kinase receptor, epidermal also efficient signaling. However, colony-stimulating 1 (whose receptor is highly related receptor) could induce synthesis absence active 3-K, as two (bombesin lysophosphatidic acid) whose receptors functionally coupled G proteins. These data, therefore, demonstrate that some, but not all, require 3-K.