High impact information on GORASP1

• GM130 and GRASP65-dependent lateral cisternal fusion allows uniform Golgi-enzyme distribution [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].
• GRASP55 is homologous to GRASP65, an N-ethylmaleimide-sensitive membrane protein required for the stacking of Golgi cisternae in a cell-free system [3].
• Golgi reassembly stacking protein 65 (GRASP65), an NEM-sensitive membrane-bound component, is required for the stacking process [4].
• Deletion or frameshift mutations in the conserved C-terminal domain of Plk greatly diminish its ability to phosphorylate GRASP65 [5].

Biological context of GORASP1

• The Golgi reassembly stacking protein (GRASP) family has been implicated in the stacking of Golgi cisternae and the regulation of Golgi disassembly/reassembly during mitosis in mammalian cells [6].
• Here, we demonstrate that ribbon formation is mediated by specific membrane-fusion events that occur during Golgi assembly, and require the Golgi proteins GM130 and GRASP65 [1].
• The Golgi-associated protein GRASP65 regulates spindle dynamics and is essential for cell division [7].
• In the absence of GRASP65, the number of cisternae per Golgi stack is reduced without affecting the overall organization of Golgi membranes and protein transport [7].
• Mitotic phosphorylation of Golgi reassembly stacking protein 55 by mitogen-activated protein kinase ERK2 [8].

Anatomical context of GORASP1

• To address the role of GRASP65 in mitotic Golgi fragmentation, we depleted the protein from HeLa cells by RNAi [7].
• We found that GM130 and GRASP65 cycle via membranous tubules between the Golgi complex and a constellation of mobile structures that we call late IC stations [9].
• In contrast, the cis-Golgi matrix proteins GM130 and GRASP65 are retained in punctate cytoplasmic structures, namely Golgi remnants [10].
• Golgin-97, a candidate trans-Golgi network matrix protein, is retained in Golgi remnant-like structures, but mostly separated from GM130 and GRASP65 [10].

Associations of GORASP1 with chemical compounds

• The MEK1 requirement for normal mitotic entry was abrogated if Golgi proteins were dispersed before M phase by treatment of cells with brefeldin A or if GRASP65, which links Golgi stacks into a ribbon network, was depleted [11].
• Saturation solubilities of several para-substituted acetanilides have been measured at 37 degrees C in aqueous solutions of structurally related polyoxyethylene-polyoxypropylene block copolymers-poloxamers L62, L63, L64, P65 and F68 [12].

Other interactions of GORASP1

• GRASP55 and GRASP65 have been shown to play a role in stacking of the Golgi cisternae in vitro [13].

References