GRASP depletion–mediated Golgi destruction decreases cell adhesion and migration via the reduction of a5ß1 integrin

Ahat, Erpan; Xiang, Yi; Zhang, Xiaoyan; Bekier, Michael E.; Wang, Yanzhuang

The exact mechanism of Golgi stack formation is not fully understood, but the two Golgi reassembly and stacking proteins (GRASPs), GRASP55 and GRASP65, are the only Golgi stacking proteins identified so far (Barr et al., 1997; Shorter et al., 1999; Xiang and Wang, 2010; Zhang and Wang, 2015) . GRASP55 and GRASP65 localize at the medial-/trans-and cis-Golgi, respectively, form transoligomers through the N-terminal GRASP domain to hold the cisternae together into stacks (Wang et al., 2005) , and link Golgi stacks into a ribbon (Puthenveedu et al., 2006) . The C-terminal serine-proline-rich domains of GRASP55 and GRASP65 are more divergent, but both are phosphorylated in mitosis to dissociate the protein trans-oligomers and disassemble the Golgi structure. In telophase, Golgi tubules and vesicles are divided equally between daughter cells, where they are reassembled into stacks and ribbons upon dephosphorylation of GRASP proteins (Vielemeyer et al., 2009; Tang et al., 2012) . Therefore, GRASPs are essential proteins for maintaining an intact and dynamic Golgi structure Wang, 2015, 2016) . In addition to GRASPs, GRASP-interacting proteins such as GM130 and Golgin 45 may also facilitate Golgi stack formation (Lee et al., 2014) .