Figure 1.

Engineered multi-PH domain constructs used in this study. Schematic diagram in which ovals represent the individual human GRP1 PH domain (residues 255–392) and other symbols represent engineered N-terminal and linker peptides (sequences as indicated). Each construct is enzymatically labeled with Alexa Fluor 555-CoA at the underlined serine residue on the N-terminal, 11-residue tagging sequence (21,23). The 2PHΔPIP3 protein contains the K273A/R284A double mutation in the first PH domain (gray) known to inactivate the PIP₃ binding site (45).