GRASP55

GRASP55

Diagram of GRASP55 domains

GRASP55 (Golgi Reassembly Stacking Protein of 55 kDa) is a protein that plays a crucial role in the Golgi apparatus structure and function. It is involved in the stacking of Golgi cisternae and is essential for maintaining the integrity of the Golgi structure during the cell cycle.

Structure

GRASP55 is characterized by its unique domain structure, which includes a PDZ domain and a GRASP domain. These domains are critical for its function in Golgi stacking and membrane tethering. The PDZ domain allows GRASP55 to interact with other proteins, while the GRASP domain is involved in membrane attachment.

Function

GRASP55 is primarily involved in the reassembly of the Golgi apparatus after mitosis. During cell division, the Golgi apparatus disassembles and then reassembles in the daughter cells. GRASP55, along with its homolog GRASP65, facilitates this reassembly process by mediating the stacking of Golgi cisternae.

Role in Golgi Apparatus

The Golgi apparatus is a central organelle in the secretory pathway of eukaryotic cells. It is responsible for modifying, sorting, and packaging proteins and lipids for secretion or delivery to other organelles. GRASP55 contributes to the structural organization of the Golgi by promoting the stacking of its cisternae, which is essential for its function.

Cellular Processes

GRASP55 is involved in various cellular processes beyond Golgi stacking. It plays a role in protein trafficking, cell signaling, and autophagy. Its function in autophagy is particularly important under stress conditions, where it helps in the formation of autophagosomes.

Interactions

GRASP55 interacts with several proteins, including GM130, a Golgi matrix protein, and Rab GTPases, which are involved in vesicle trafficking. These interactions are crucial for its role in Golgi reassembly and function.

Related pages

• Golgi apparatus
• GRASP65
• Protein trafficking
• Autophagy