The Yeast GRASP Grh1 Colocalizes with COPII and Is Dispensable for Organizing the Secretory Pathway

Levi, Stephanie; Bhattacharyya, Dibyendu; Strack, Rita; Austin, Jotham R.; Glick, Benjamin S.

doi:10.1111/j.1600-0854.2010.01089.x

Cited by 71 publications

(97 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the simpler case of Drosophila, dsRNA-mediated depletion of dGRASP results in ∼30% loss of Golgi stacks, whereas double depletion of dGRASP and dGM130 was shown to unstack the Golgi, as examined by EM (21). In Schizosaccharomyces pombe, depletion of yeast GRASP homolog Grh1 has no effect on Golgi stacking (22). This situation can be extended to plants, where no GRASP or even Golgin homolog has been identified thus far (23).…”

mentioning

confidence: 75%

Membrane adhesion dictates Golgi stacking and cisternal morphology

Lee

Tiwari

Dunlop

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Two classes of proteins that bind to each other and to Golgi membranes have been implicated in the adhesion of Golgi cisternae to each other to form their characteristic stacks: Golgi reassembly and stacking proteins 55 and 65 (GRASP55 and GRASP65) and Golgin of 45 kDa and Golgi matrix protein of 130 kDa. We report here that efficient stacking occurs in the absence of GRASP65/55 when either Golgin is overexpressed, as judged by quantitative electron microscopy. The Golgi stacks in these GRASP-deficient HeLa cells were normal both in morphology and in anterograde cargo transport. This suggests the simple hypothesis that the total amount of adhesive energy gluing cisternae dictates Golgi cisternal stacking, irrespective of which molecules mediate the adhesive process. In support of this hypothesis, we show that adding artificial adhesive energy between cisternae and mitochondria by dimerizing rapamycin-binding domain and FK506-binding protein domains that are attached to cisternal adhesive proteins allows mitochondria to invade the stack and even replace Golgi cisternae within a few hours. These results indicate that although Golgi stacking is a highly complicated process involving a large number of adhesive and regulatory proteins, the overriding principle of a Golgi stack assembly is likely to be quite simple. From this simplified perspective, we propose a model, based on cisternal adhesion and cisternal maturation as the two core principles, illustrating how the most ancient form of Golgi stacking might have occurred using only weak cisternal adhesive processes because of the differential between the rate of influx and outflux of membrane transport through the Golgi.tethers | GRASPs T he Golgi apparatus plays a central role in the processing, sorting, and secretion of various cargo molecules destined for various intracellular and extracellular destinations (1). In animal and plant cells, its unique structure of four to six stacked, roughly planar cisternae serves, among other things, as a platform to organize Golgi resident glycosyltransferases into distinct membrane-bound subcompartments (the cis-, medial-, and trans-Golgi cisternae) for proper and sequential posttranslational maturation of the transiting cargo proteins (2, 3).Although these characteristic features of Golgi morphology have drawn the attention of many researchers for many decades, the molecular mechanisms underlying them are still unclear (4). Pioneering functional reconstitution studies using a cell-free system in which Golgi stacks (but not ribbons) reassemble from mitotic extracts (5-8) yielded two classes of purified proteins, each clearly contributing to stacking: globular Golgi reassembly and stacking proteins (GRASPs; the homologous proteins GRASP65 and GRASP55) (7, 9) and the helical rod-like and partially homologous proteins Golgi matrix protein of 130 kDa (GM130) and Golgin of 45 kDa (Golgin45) (10, 11). One member of each family (GRASP65 and GM130) is located in the cis-most cisterna (7, 12), and another member of each family (GRASP5...

show abstract

mentioning

confidence: 75%

Membrane adhesion dictates Golgi stacking and cisternal morphology

Lee

Tiwari

Dunlop

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…First, we examined transitional endoplasmic reticulum (tER) sites, which produce COPII vesicles (Rossanese et al, 1999;Shindiapina and Barlowe, 2010). Some mutations cause coalescence of these structures (Castillon et al, 2009;Levi et al, 2010;Shindiapina and Barlowe, 2010), but we saw no consistent differences in the tER patterns of wild-type and arf1D cells (supplementary material Fig. S2), suggesting that the arf1D mutation acts at the level of the Golgi.…”

Section: Golgi Enlargement Can Be Caused By Reduced Arf Activitymentioning

confidence: 99%

Golgi enlargement in Arf-depleted yeast cells is due to altered dynamics of cisternal maturation

Bhave

Papanikou

Iyer

et al. 2013

Journal of Cell Science

Self Cite

View full text Add to dashboard Cite

Regulation of the size and abundance of membrane compartments is a fundamental cellular activity. In Saccharomyces cerevisiae, disruption of the ADP-ribosylation factor 1 (ARF1) gene yields larger and fewer Golgi cisternae by partially depleting the Arf GTPase. We observed a similar phenotype with a thermosensitive mutation in Nmt1, which myristoylates and activates Arf. Therefore, partial depletion of Arf is a convenient tool for dissecting mechanisms that regulate Golgi structure. We found that in arf1D cells, late Golgi structure is particularly abnormal, with the number of late Golgi cisternae being severely reduced. This effect can be explained by selective changes in cisternal maturation kinetics. The arf1D mutation causes early Golgi cisternae to mature more slowly and less frequently, but does not alter the maturation of late Golgi cisternae. These changes quantitatively explain why late Golgi cisternae are fewer in number and correspondingly larger. With a stacked Golgi, similar changes in maturation kinetics could be used by the cell to modulate the number of cisternae per stack. Thus, the rates of processes that transform a maturing compartment can determine compartmental size and copy number.

show abstract

“…2E). After a brief incubation of the culture in glucose-free medium prior to microscopy, which results in coalescence of ER exit sites (Levi et al, 2010), cells with especially evident Chs2-3xGFP colocalization with Sec13-mCherry were observed (Fig. 2F).…”

Section: Chs2p Accumulates At Er Exit Sites In Metaphase-arrested Cellsmentioning

confidence: 99%

“…In S. cerevisiae, ER exit sites appear as numerous small puncta continuous with the ER when visualized with a fluorescently tagged Sec13p (Rossanese et al, 1999;Castillon et al, 2009;Levi et al, 2010;Shindiapina and Barlowe;. Because of the punctate appearance of Chs2-3xGFP in arrested cells (Fig.…”

Section: Chs2p Accumulates At Er Exit Sites In Metaphase-arrested Cellsmentioning

confidence: 99%

See 1 more Smart Citation

Phosphorylation of Chs2p regulates interaction with COPII

Jakobsen¹,

Cheng²,

Lam³

et al. 2013

Journal of Cell Science

View full text Add to dashboard Cite

SummaryTrafficking of the chitin synthase Chs2p from the endoplasmic reticulum (ER) to the bud-neck in late mitosis is tightly regulated by the cell cycle via phosphorylation of serine residues in the N-terminus of the protein. Here, we describe the effects of Chs2p phosphorylation on the interaction with coat protein complex II (COPII). Identification of a cdc5 ts mutant, which fails to transport Chs2p-3xGFP to the bud-neck and instead accumulates the protein in intracellular puncta, led us to discover that Chs2p-3xGFP accumulates at ER exit sites in metaphase-arrested wild-type cells. Using an in vitro ER vesicle formation assay we showed that phosphorylation of Chs2p by the cyclin-dependent kinase CDK1 prevents packaging into COPII vesicles, whereas dephosphorylation of Chs2p by the phosphatase Cdc14p stimulates selection into the vesicles. We found that the cytoplasmic N-terminal domain of Chs2p, which contains the CDK1 phosphorylation sites, interacts with the COPII component Sec24p in a yeast two-hybrid assay and that phosphomimetic substitutions of serines at the CDK1 consensus sites reduces the interaction. Our data suggest that dephosphorylation functions as a molecular switch for regulated ER exit of Chs2p.

show abstract

The Yeast GRASP Grh1 Colocalizes with COPII and Is Dispensable for Organizing the Secretory Pathway

Cited by 71 publications

References 67 publications

Membrane adhesion dictates Golgi stacking and cisternal morphology

Membrane adhesion dictates Golgi stacking and cisternal morphology

Golgi enlargement in Arf-depleted yeast cells is due to altered dynamics of cisternal maturation

Phosphorylation of Chs2p regulates interaction with COPII

Contact Info

Product

Resources

About