TY - JOUR
T1 - The pleckstrin homology domain of Gab-2 is required for optimal interleukin-3 signalsome-mediated responses
AU - Edmead, C E
AU - Fox, B C
AU - Stace, C
AU - Ktistakis, N
AU - Welham, M J
PY - 2006
Y1 - 2006
N2 - The adaptor protein Gab-2 coordinates the assembly of the IL-3 signalsome comprising Gab-2, Grb2, Shc, SHP-2 and PI3K. To investigate the role of the pleckstrin homology domain of Gab-2 in this process, epitope-tagged wild type Gab-2 (WTGab-2), Gab-2 lacking its PH domain (ΔPHGab-2) and the Gab-2 PH domain alone (PHGab-2) were inducibly expressed in IL-3-dependent BaF/3 cells. Expression of ΔPHGab-2 reduced IL-3-dependent proliferation and long-term activation of ERK1 and 2 and PKB by IL-3. While we demonstrate that the Gab-2 PH domain can bind PI(3,4,5)P3, it is dispensable for Gab-2 membrane localisation, tyrosine phosphorylation and signalsome formation. Rather, the proline-rich motifs of Gab-2 appear to contribute to the constitutive membrane localisation we observe, independently of tyrosine phosphorylation or the PH domain. Taken together, these findings suggest that once Gab-2 is tyrosine phosphorylated its PH domain is required for the optimal stabilisation of the signalsome, enabling full activation of downstream signals.
AB - The adaptor protein Gab-2 coordinates the assembly of the IL-3 signalsome comprising Gab-2, Grb2, Shc, SHP-2 and PI3K. To investigate the role of the pleckstrin homology domain of Gab-2 in this process, epitope-tagged wild type Gab-2 (WTGab-2), Gab-2 lacking its PH domain (ΔPHGab-2) and the Gab-2 PH domain alone (PHGab-2) were inducibly expressed in IL-3-dependent BaF/3 cells. Expression of ΔPHGab-2 reduced IL-3-dependent proliferation and long-term activation of ERK1 and 2 and PKB by IL-3. While we demonstrate that the Gab-2 PH domain can bind PI(3,4,5)P3, it is dispensable for Gab-2 membrane localisation, tyrosine phosphorylation and signalsome formation. Rather, the proline-rich motifs of Gab-2 appear to contribute to the constitutive membrane localisation we observe, independently of tyrosine phosphorylation or the PH domain. Taken together, these findings suggest that once Gab-2 is tyrosine phosphorylated its PH domain is required for the optimal stabilisation of the signalsome, enabling full activation of downstream signals.
UR - http://dx.doi.org/10.1016/j.cellsig.2005.09.002
U2 - 10.1016/j.cellsig.2005.09.002
DO - 10.1016/j.cellsig.2005.09.002
M3 - Article
SN - 0898-6568
VL - 18
SP - 1147
EP - 1155
JO - Cellular Signalling
JF - Cellular Signalling
IS - 8
ER -