Golgi reassembly-stacking protein 2 ( GRS2) also known as Golgi reassembly-stacking protein of 55 kDa (GRASP55) is a protein that in humans is encoded by the GORASP2gene.[5] It was identified by its homology with GORASP1 and the protein's amino acid sequence was determined by analysis of a molecular clone of its complementary DNA.[6] The first (N-terminus) 212 amino acid residues of GORASP2 are highly homologous to those of GORASP1, but the remainder of the 454 amino acid residues are highly diverged from GORASP1.[6] The conserved region is known as the GRASP domain, and it is conserved among GRASPs of a wide variety of eukaryotes, but not plants.[5][7] The C-terminus portion of the molecule is called the SPR domain (serine, proline-rich).[7] GORASP2 is more closely related to homologues in other species, suggesting that GORASP2 is ancestral to GORASP1.[7] GORASP2 is found associated with the medial and trans cisternae of the Golgi apparatus.[7]
GORASP2 is involved in establishing the structure of the Golgi apparatus.[7][5] It is a peripheral membrane protein located on the Golgi cisterna, and it can bind to another GRS2 located on an adjacent cisterna through the GRASP domain, thus linking the cisternae together through multiple protein–protein interactions.[7][8]
GRS2 is attached to the membrane in two ways; it is myristylated, which attaches it directly to the lipid bilayer; it is also bound indirectly by binding to golgin-45, which binds to a Rab protein, which itself is lipidated and thus anchored to the membrane.[7]
The structure of the Golgi is disrupted during mitosis, and phosphorylation of the SPR domains of GORASP2 and GORASP1 regulate that disruption,[9][8] GORASP2 may also be involved in forming Golgi ribbons, but the evidence is mixed.[7][9]
Maruyama K, Sugano S (January 1994). "Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides". Gene. 138 (1–2): 171–4. doi:10.1016/0378-1119(94)90802-8. PMID8125298.
Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K, Suyama A, Sugano S (October 1997). "Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library". Gene. 200 (1–2): 149–56. doi:10.1016/S0378-1119(97)00411-3. PMID9373149.
Beausoleil SA, Villén J, Gerber SA, Rush J, Gygi SP (October 2006). "A probability-based approach for high-throughput protein phosphorylation analysis and site localization". Nature Biotechnology. 24 (10): 1285–92. doi:10.1038/nbt1240. PMID16964243. S2CID14294292.
