GRP1 Associated Scaffold Protein (GRASP)

The deduced 392-amino acid protein has an alanine/proline-rich N-terminal region containing an Src homology-3 domain-binding site (PxxP), followed by a PDZ domain and a leucine-rich domain. It shares substantial similarity with proteins of the MAGUK family and with RGS12. RT-PCR detected high expression in mouse brain, moderate expression in lung and heart, and low expression in kidney, ovary, and embryo. Epitope-tagged Grasp localized to the plasma membrane of transfected human embryonic kidney cells.Grasp also interacted with the N-terminal coiled-coil domain of cytohesin-2 (PSCD2) in pull-down assays. In transfected HEK293 cells, Grasp enhanced Grp1 association with the plasma membrane and also colocalized with endogenous ADP-ribosylation factors at the plasma membrane.