Maintenance of the Golgi Ribbon Structure by the KASH Protein Jaw1.

The Golgi apparatus is an organelle responsible for modification, secretion, and transport of biomolecules. Its structure and morphology are crucial for the efficient processing and proper transport of proteins. The maintenance of this Golgi ribbon structure involves multiple proteins including GRASP and golgin proteins and the microtubule network. Particularly, the microtubule network extending from the Golgi is important for the Golgi ribbon formation and positioning. A recent report by Okumura et al. (J. Biochem. 2023; 173: 383-392) demonstrated that Jaw1, one of the Klarsicht/ANC-1/Syne/homology (KASH) proteins that are components of the linker of nucleoskeleton and cytoskeleton (LINC) complex, is essential for maintaining the Golgi ribbon structure. Knockdown of Jaw1 disrupted the Golgi ribbon structure leading to the fragmentation, while the Golgi ministacks were preserved. Acetylated tubulin, a marker of the Golgi-derived microtubule network, became more dispersed, losing its local compactness in the Jaw-depleted cells. These phenomena suggest that Jaw1 is required to maintain the proper organization of the Golgi-derived microtubule network.