How Rab Proteins Determine Golgi Structure

Abstract

Rab proteins, small GTPases, are key regulators of mammalian Golgi apparatus organization. Based on the effect of Rab activation state, Rab proteins fall into two functional classes. In Class1, inactivation induces Golgi ribbon fragmentation and/or redistribution of Golgi enzymes to the ER, while overexpression of wild type or activation has little, if any, effect on Golgi ribbon organization. In Class 2, the reverse is true. We give emphasis to Rab6, the most abundant Golgi-associated Rab protein. Rab6 depletion in HeLa cells causes an increase in Golgi cisternal number, longer, more continuous cisternae, and a pronounced accumulation of vesicles; the effect of Rab6 on Golgi ribbon organization is probably through regulation of vesicle transport. In effector studies, motor proteins and their regulators are found to be key Rab6 effectors. A related Rab, Rab41, affects Golgi ribbon organization in a contrasting manner. The balance between minus- and plus-end directed motor recruitment may well be the major Rab-dependent factor in Golgi ribbon organization.

Rab‐mediated trafficking in the secondary cells of Drosophila male accessory glands and its role in fecundity

“…The distribution of Rab6 in SCs is somewhat similar to SG cells, where Rab6 is found on Golgi but also on non‐Golgi compartments . Nevertheless, the extreme enlargement of all Rab6 compartments in the SCs and the more‐differentiated morphology of the Golgi, point to extensive membrane/protein transport processes …”

N‐terminal autoprocessing and acetylation of multifunctional‐autoprocessing repeats‐in‐toxins (MARTX) Makes Caterpillars Floppy‐like effector is stimulated by adenosine diphosphate (ADP)‐Ribosylation Factor 1 in advance of Golgi fragmentation

“…Depending on the isoform, they localize to specific subcellular locations, including the Golgi, plasma membrane, and endosomes. The Golgi apparatus is generally composed of tight perinuclear Golgi stacks and plays a central role in membrane trafficking, wherein it receives, post-translationally modifies and sorts proteins from the ER to their appropriate destinations (Liu & Storrie, 2015;Wei & Seemann, 2010). At the Golgi, ARF1 is recognized by its guanine nucleotide exchange factors (GEF), inducing a In this study, we show that the pro-form of the V. vulnificus MARTX effector MCF is activated by autoprocessing upon binding with Class I ARF1 and ARF3.…”

“…As expected, at 10 hr after transfection, PBS mock transfected HeLa cells showed a Golgi with typical stacked morphology (Figure 7a, green G). The Golgi apparatus is generally composed of tight perinuclear Golgi stacks and plays a central role in membrane trafficking, wherein it receives, post-translationally modifies and sorts proteins from the ER to their appropriate destinations(Liu & Storrie, 2015;Wei & Seemann, 2010). At higher magnification, it FIGURE 6 Makes Caterpillars Floppy (MCF) disrupts the mitochondrial network.…”

N-terminal autoprocessing and acetylation of MARTX Makes-Caterpillars Floppy-like effector is stimulated by ADP-Ribosylation Factor 1 in advance of Golgi fragmentation

“…Depending on the isoform, they localize to specific subcellular locations, including the Golgi, plasma membrane, and endosomes. The Golgi apparatus is generally composed of tight perinuclear Golgi stacks and plays a central role in membrane trafficking, wherein it receives, post-translationally modifies and sorts proteins from the ER to their appropriate destinations (Liu & Storrie, 2015;Wei & Seemann, 2010). At the Golgi, ARF1 is recognized by its guanine nucleotide exchange factors (GEF), inducing a conformational change that exposes its N-terminal amphipathic helix so that it binds GTP in place of GDP (Behnia, Panic, Whyte, & Munro, 2004).…”