GRASP55

Golgi reassembly-stacking protein of 55 kDa (GRASP55) also known as golgi reassembly-stacking protein 2 (GORASP2) is a protein that in humans is encoded by the GORASP2 gene.^[5][6] It was identified by its homology with GRASP65 and the protein's amino acid sequence was determined by analysis of a molecular clone of its complementary DNA.^[5] The first (N-terminus) 212 amino acid residues of GRASP55 are highly homologous to those of GRASP65, but the remainder of the 454 amino acid residues are highly diverged from GRASP65.^[5] The conserved region is known as the GRASP domain, and it is conserved among GRASPs of a wide variety of eukaryotes, but not plants.^[6][7] The C-terminus portion of the molecule is called the SPR domain (serine, proline-rich).^[7] GRASP55 is more closely related to homologues in other species, suggesting that GRASP55 is ancestral to GRASP65.^[7] GRASP55 is found associated with the medial and trans cisternae of the Golgi apparatus.^[7]

GORASP2
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 3RLE, 4EDJ
Identifiers
Aliases	GORASP2, GOLPH6, GRASP55, GRS2, p59, golgi reassembly stacking protein 2
External IDs	OMIM: 608693; MGI: 2135962; HomoloGene: 9180; GeneCards: GORASP2; OMA:GORASP2 - orthologs
Gene location (Human) Chr. Chromosome 2 (human)[1] Band 2q31.1 Start 170,928,464 bp[1] End 170,967,130 bp[1]
Gene location (Mouse) Chr. Chromosome 2 (mouse)[2] Band 2|2 C2 Start 70,491,920 bp[2] End 70,542,980 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in sperm secondary oocyte endothelial cell tibia parotid gland islet of Langerhans stromal cell of endometrium cartilage tissue corpus epididymis palpebral conjunctiva Top expressed in Ileal epithelium lacrimal gland parotid gland seminal vesicula calvaria crypt of lieberkuhn of small intestine secondary oocyte molar islet of Langerhans stroma of bone marrow More reference expression data BioGPS More reference expression data
Gene ontology Molecular function protein binding Cellular component Golgi membrane membrane Golgi apparatus endoplasmic reticulum endoplasmic reticulum membrane Biological process organelle organization Golgi organization organelle assembly spermatogenesis cell differentiation response to endoplasmic reticulum stress establishment of protein localization to plasma membrane Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 26003 70231 Ensembl ENSG00000115806 ENSMUSG00000014959 UniProt Q9H8Y8 Q99JX3 RefSeq (mRNA) NM_001201428 NM_015530 NM_027352 RefSeq (protein) NP_001188357 NP_056345 NP_081628 Location (UCSC) Chr 2: 170.93 – 170.97 Mb Chr 2: 70.49 – 70.54 Mb PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Function

GRASP domain alignment of GRASP55 and the GRASP homologue of Cryptococcus neoformans

GRASP55 is involved in establishing the structure of the Golgi apparatus.^[7][6] It is a peripheral membrane protein located on the Golgi cisterna, and it can bind to another GRASP55 located on an adjacent cisterna through the GRASP domain, thus linking the cisternae together through multiple protein–protein interactions.^[7][8]

GRASP55 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 GRASP55 and GRASP65 regulate that disruption,^[9][8] GRASP55 may also be involved in forming Golgi ribbons, but the evidence is mixed.^[7][9]

Other interactions

GRASP55 has been shown to interact with TGF alpha,^[10] TMED2^[10] and GOLGA2.^[5][10][11]