Golgi matrix

[4] Modern freeze etch[5] electron microscopy (EM) clearly shows a mesh connecting Golgi cisternae and associated vesicles.

[6][7] Further support for the existence of a matrix comes from EM images showing that ribosomes are excluded from regions between and near Golgi cisternae.

[15][1] For example, GMAP210 (Golgi Microtubule Associated Protein 210) has an ALPS (Amphipathic Lipid-Packing Sensor) motif in the N-termal 38 amino acids and an ARF1-binding domain called GRAB (Grip-Related Arf-Binding) at the C-terminus.

[16] Thus, the GRAB-domain can bind indirectly to Golgi cisternae and its ALPS motif can tether vesicles.

[7] Their trans oligomerization is controlled by phosphorylation[6] and is thought to explain the fragmentation of the Golgi as required during mitosis.

The Golgin GMAP210 has functional regions at both ends.
The ALPS of GMAP210 binds to curved, but not flat, lipid layers
GRASP domain alignment of GRASP55 and the GRASP homologue of Cryptococcus neoformans
Microinjection of antibodies to GRASP65 prevents normal Golgi stack formation.