|
Leonard (Len) R Stephens FRS〔http://royalsociety.org/people/leonard-stephens/ retrieved January 12, 2014〕 (born 18 June 1960) is a molecular biologist, senior group leader and associate director at the Babraham Institute. Len Stephens has contributed much to the understanding of inositol lipids functions in eukaryotic cells, and in particular in neutrophils. Early highlights were the mapping of new pathways of inositol phosphate synthesis.〔L.R. Stephens, K.T. Hughes, R.F. Irvine (1991) Pathway of phosphatidylinositol(3,4,5)-trisphosphate synthesis in activated neutrophils. ''Nature'' 351, 33-39〕 Together with his long-time collaborator Phillip Thomas Hawkins, he established that PtdIns(4,5)P2 is the main substrate of receptor-controlled Type 1 phosphoinositide 3-kinases (PI3Ks), thus identifying PtdIns(3,4,5)P3 as the key output signal produced by this enzyme.〔P.T. Hawkins, T.R. Jackson, L.R. Stephens (1992) Platelet-derived growth factor stimulates synthesis of Ptdlns(3,4,5)P3 by activating a Ptdlns(4,5)P2 3-OH kinase. ''Nature'' 358, 157-159〕 They identified and isolated the GPCR-activated Type 1B PI3K (PI3KΥ) and, in a sustained body of work, defined its structure, explained its complex pattern of regulation by GβΥ and Ras, and proved its role in inflammatory events ''in vivo''.〔L. Stephens, A. Smrcka, F.T. Cooke, T.R. Jackson, P.C. Sternweis, P.T. Hawkins (1994) A novel phosphoinositide 3 kinase activity in myeloid-derived cells is activated by G protein βγ subunits. ''Cell'' 77, 83-93〕 They – in parallel with Dario Alessi – identified phosphoinositide-dependent kinase-1 as the PtdIns(3,4,5)P3-activated link between PI3K-1 activation and protein kinase B activation, a key pathway through which PtdIns(3,4,5)P3 formation regulates cell proliferation and survival.〔Stephens L.R., Anderson K., Stokoe D., Erdjument-Bromage H., Painter G.F., Holmes A.B., Gaffney P.R.J., Reese C.B., McCormick F., Tempst P., Coadwell J., Hawkins P.T. (1998) Protein Kinase B Kinases That Mediate Phosphatidylinositol 3,4,5-Trisphosphate-Dependent Activation of Protein Kinase B. ''Science'' 279, 710-714〕 Later, they showed that PtdIns(3,4,5)P3 was responsible for the recruitment of both PKB and PDK1 to the membrane, and therefore the activation of the former by the latter. == Life == Len Stephens received a BSc in Biology (1981) and a PhD in Physiology (1984) from the University of Birmingham. After a post-doctoral training in S.K. & F. Research Ltd, he joined the AFRC IAPGR (now Babraham Institute). He became a staff scientist in the Inositide laboratory in 1992 and took the leadership of the laboratory in 1996. In 2008, he became associate director of the Babraham Institute. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Leonard R. Stephens」の詳細全文を読む スポンサード リンク
|