GRIP1 Associated Protein 1 (GRIPAP1)

GRASP1 is a neuron-specific guanine nucleotide exchange factor for the Ras family of small G proteins (RasGEF) and is associated with the GRIP/AMPA receptor complex in brain.

GRASP1 cDNA encodes an 838-amino acid protein. Two splicing isoforms were observed. Sequence analysis revealed that GRASP1 has a RasGEF catalytic domain, a potential caspase-3 cleavage site, a region weakly homologous to the Ras-binding protein of ralGDS, and a PDZ domain. This overall domain structure is similar to that of ralGDS, which contains an N-terminal GEF catalytic domain and a C-terminal regulatory domain.Unlike most PDZ domain-interacting proteins, GRASP1 does not contain a characterized type I or type II PDZ ligand at its C terminus.