Catalytic competence of the Ras-GEF domain of hSos1 requires intra-REM domain interactions mediated by phenylalanine 577.
The Ras-specific guanine nucleotide exchange region of hSos1 consists of two consecutive domains: the catalytic core (residues 742-1024) contains all residues binding to Ras, including the catalytic hairpin, and an upstream REM domain (residues 553-741), so called because it contains an evolutionary conserved Ras Exchange Motif (REM). We functionally define the boundaries of the REM domain through a combination of in vivo and in vitro assays. We show that an intra-REM domain interaction, mediated by phenylalanine 577, is required to allow interaction of the REM domain with the catalytic core, constraining it in the active conformation.
Sacco
Elena
E
Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy.
Metalli
David
D
Busti
Stefano
S
Fantinato
Sonia
S
D'Urzo
Annalisa
A
Mapelli
Valeria
V
Alberghina
Lilia
L
Vanoni
Marco
M
D020816:Amino Acid Motifs / Q000235:genetics; D001665:Binding Sites; D006801:Humans; D010649:Phenylalanine / Q000737:chemistry / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D020837:SOS1 Protein / Q000737:chemistry* / Q000235:genetics
D020837:SOS1 Protein; D010649:Phenylalanine