New components of the Golgi matrix

Abstract

The eukaryotic Golgi apparatus is characterized by a stack of flattened cisternae that are surrounded by transport vesicles. The organization and function of the Golgi require Golgi matrix proteins, including GRASPs and golgins, which exist primarily as fiber-like bridges between Golgi cisternae or between cisternae and vesicles. In this review, we highlight recent findings on Golgi matrix proteins, including their roles in maintaining the Golgi structure, vesicle tethering, and novel, unexpected functions. These new discoveries further our understanding of the molecular mechanisms that maintain the structure and the function of the Golgi, as well as its relationship with other cellular organelles such as the centrosome.

Aβ-induced Golgi fragmentation in Alzheimer’s disease enhances Aβ production

“…Golgi membranes form a unique stacked structure. This structure is maintained by Golgi structural proteins (11,12), and Golgi fragmentation may be caused by a modification of these proteins, as has been suggested by Sun et al (13). In that study, the authors showed that cyclin-dependent kinase-5 (cdk5) is activated by the addition of synthetic Aβ peptides into the tissue culture medium, which subsequently phosphorylates GM130 and causes Golgi fragmentation.…”

“…Formation of the highly organized stacked Golgi structure is mediated by Golgi structural proteins (12), including GRASP65 (25), GRASP55 (26), GM130 (16), golgin-160 (27), and p115 (28). Among these proteins, GRASP65 and GRASP55 play essential roles in Golgi structure formation, whereas the others are important for trafficking across the Golgi stack.…”

Connecting the Cytoskeleton to the Endoplasmic Reticulum and Golgi

“…This matrix is necessary for tethering transport vesicles as well as for maintenance of cisternal associations both longitudinally within mini-stacks and laterally between mini-stacks[103]. Made up primarily of peripheral membrane proteins in the GRASP and golgin families, the matrix is highly dynamic as these coiled-coil proteins associate and disassociate both with the Golgi and with each other, in part controlled by well-known kinase pathways[104].…”

Intracellular Scaling Mechanisms

“…Such molecular rulers could include structures, such as the putative spindle matrix (Schweizer et al 2014) and Golgi matrix (Xiang and Wang 2011), which have been proposed to be composed of complex molecular networks. Although these structures are presumably subject to size control and, at least in the case of the spindle matrix, also subject to cell-size-dependent scaling, we know little about how their size is controlled and even less about how their size is scaled appropriately to the size of the cell.…”