GORASP2
Description
The GORASP2 (golgi reassembly stacking protein 2) is a protein-coding gene located on chromosome 2.
GORASP2, also known as Golgi reassembly-stacking protein of 55 kDa (GRASP55), is a protein encoded by the GORASP2 gene in humans. It shares homology with GRASP65, particularly in its N-terminal region (first 212 amino acids), which contains the conserved GRASP domain. The remaining C-terminal portion is distinct from GRASP65 and contains a SPR domain (serine, proline-rich). GRASP55 is more closely related to homologues in other species, suggesting its ancestral origin. It is associated with the medial and trans cisternae of the Golgi apparatus and plays a role in establishing the structure of the Golgi. GRASP55 acts as a peripheral membrane protein, binding to adjacent cisternae through its GRASP domain, linking them together. Its attachment to the membrane occurs through myristylation and indirect binding to golgin-45, which interacts with a Rab protein that is lipidated and anchored to the membrane. During mitosis, the structure of the Golgi is disrupted, and phosphorylation of the SPR domains of GRASP55 and GRASP65 regulates this process. GRASP55 may also be involved in forming Golgi ribbons, although the evidence is inconclusive.
GORASP2 is a key structural protein of the Golgi apparatus. It plays a role in the formation and maintenance of the Golgi ribbon, working in conjunction with GORASP1/GRASP65. While it may be dispensable for the formation of Golgi stacks, other studies indicate its involvement in the assembly and stacking of Golgi cisternae, as well as in the reassembly process after their breakdown during mitosis and meiosis. GORASP2 might also regulate the intracellular transport and presentation of specific transmembrane proteins, such as transmembrane TGFA. Its role in normal acrosome formation during spermiogenesis and male fertility is likely due to its promotion of JAM2 and JAM3 colocalization at contact points between germ cells and Sertoli cells. Moreover, GORASP2 mediates the unconventional ER/Golgi-independent trafficking of core-glycosylated CFTR to the cell membrane in response to ER stress.
GORASP2 is also known as GOLPH6, GRASP55, GRS2, p59.
Associated Diseases
- type 1 diabetes mellitus
- male infertility with teratozoospermia due to single gene mutation
- partial chromosome Y deletion
- spermatogenic failure 65
- spermatogenic failure, X-linked, 3
- spermatogenic failure 40
- spermatogenic failure 72
