High impact information on GORASP2

• A GRASP55-rab2 effector complex linking Golgi structure to membrane traffic [1].
• This structure is maintained by an exoskeleton or Golgi matrix constructed from a family of coiled-coil proteins, the golgins, and other peripheral membrane components such as GRASP55 and GRASP65 [2].
• Our observations suggest a role for membrane tethering of p59/GRASP55 to select transmembrane proteins, including TGF-alpha, in maturation and transport to the cell surface [3].
• Transmembrane transforming growth factor-alpha tethers to the PDZ domain-containing, Golgi membrane-associated protein p59/GRASP55 [3].
• Furthermore, expression of the GRASP family member GRASP55 after alanine substitution of its MEK1-dependent mitotic phosphorylation sites inhibited both late G(2) Golgi unlinking and the G(2)/M transition [4].

Biological context of GORASP2

• This phosphorylation was prevented by mutation of ERK consensus sites in GRASP55 [5].
• These results are the first demonstration of GRASP55 mitotic phosphorylation and indicate that the MKK/ERK pathway directly phosphorylates the Golgi during mitosis [5].

Enzymatic interactions of GORASP2

• Furthermore, ERK2 directly phosphorylated GRASP55 on the same residues that generated the MPM2 phospho-epitope [5].

Other interactions of GORASP2

• GRASP55 and GRASP65 have been shown to play a role in stacking of the Golgi cisternae in vitro [3].
• Significant amounts of the medial-Golgi matrix proteins golgin-45, GRASP55 and giantin are retained in the Golgi remnants, but a fraction of these proteins relocates to the ER [6].

References