| First Author | Lu-Kuo JM | Year | 2000 |
| Journal | J Biol Chem | Volume | 275 |
| Issue | 8 | Pages | 6022-9 |
| PubMed ID | 10681597 | Mgi Jnum | J:60675 |
| Mgi Id | MGI:1353786 | Doi | 10.1074/jbc.275.8.6022 |
| Citation | Lu-Kuo JM, et al. (2000) Impaired kit- but not FcepsilonRI-initiated mast cell activation in the absence of phosphoinositide 3-kinase p85alpha gene products. J Biol Chem 275(8):6022-9 |
| abstractText | The class I(A) phosphoinositide 3-kinases (PI3Ks) consist of a 110-kDa catalytic domain and a regulatory subunit encoded by the p85alpha, p85beta, or p55gamma genes. We have determined the effects of disrupting the p85alpha gene on the responses of mast cells stimulated by the cross-linking of Kit and FcepsilonRI, receptors that reflect innate and adaptive responses, respectively. The absence of p85alpha gene products partially inhibited Kit ligand/stem cell factor-induced secretory granule exocytosis, proliferation, and phosphorylation of the serine/threonine kinase Akt. In contrast, p85alpha gene products were not required for FcepsilonRI-initiated exocytosis and phosphorylation of Akt. LY294002, which inhibits all classes of PI3Ks, strongly suppressed Kit- and FcepsilonRI-induced responses in p85alpha -/- mast cells, revealing the contribution of another PI3K family member(s). In contrast to B lymphocytes, mast cell proliferation was not dependent on Bruton's tyrosine kinase, a downstream effector of PI3K, revealing a distinct pathway of PI3K-dependent proliferation in mast cells. Our findings represent the first example of receptor-specific usage of different PI3K family members in a single cell type. In addition, because Kit- but not FcepsilonRI-initiated signaling is associated with mast cell proliferation, the results provide evidence that distinct biologic functions signaled by these two receptors may reflect differential usage of PI3Ks. |
