Functional Roles for the Pleckstrin and Dbl Homology Regions in the Ras Exchange Factor Son-of-sevenless

Disabled-2 (Dab2) is an SH3 domain-binding partner of Grb2

“…Grb2 is composed of one SH2 and two SH3 domains, and it serves as an adaptor protein to attach cellular proteins to the tyrosine kinase receptor (Chardin et al, 1995;Downward 1994). Although recent studies indicated that the recruitment model is over-simpli®ed (McCollam et al, 1995;Byrne et al, 1996;Chen et al, 1997), the general thought is that the SH2 domain of Grb2 senses and binds the phosphorylated tyrosine residue of the activated receptor. The signalling proteins, the partners of Grb2, which are bound to the two SH3 domains of Grb2, are then recruited to the receptor.…”

Interferonγ Activation of Raf-1 Is Jak1-dependent and p21ras-independent

“…Ras Activation Assay-The activation state of p21 ras was performed as described elsewhere (19,20). 100-mm dishes of HeLa cells were labeled with 1mCi/ml [ 32 P]orthophosphate for 4 h at 37°C in phosphate-free Dulbecco's modified Eagle's medium.…”

EGF induced SOS phosphorylation in PC12 cells involves P90 RSK-2

“…In addition, studies done in Drosophila and in mammalian cells indicate that sequences contained within the amino-terminal region of SOS, including the PH and DBL domains, may be involved in stimulating the exchange activity Karlovich et al, 1995;Byrne et al, 1996). In contrast, sequences contained within the proline-rich carboxy-terminal region of SOS which mediate binding to Grb2, may be involved in down regulating the exchange activity towards Ras (Wang et al, 1995;Karlovich et al, 1995;McCollam et al, 1995). Therefore a combination of proper localization of SOS at the membrane and subsequent binding of activators and e ectors may be necessary for full activation of the exchange factor in vivo.…”