Vacuolar Storage Proteins Are Sorted in the Cis-Cisternae of the Pea Cotyledon Golgi Apparatus

Developing pea cotyledons contain functionally different vacuoles, a protein storage vacuole and a lytic vacuole. Lumenal as well as membrane proteins of the protein storage vacuole exit the Golgi apparatus in dense vesicles rather than in clathrin-coated vesicles (CCVs). Although the sorting receptor for vacuolar hydrolases BP-80 is present in CCVs, it is not detectable in dense vesicles. To localize these different vacuolar sorting events in the Golgi, we have compared the distribution of vacuolar storage proteins and of α-TIP, a membrane protein of the protein storage vacuole, with the distribution of the vacuolar sorting receptor BP-80 across the Golgi stack. Analysis of immunogold labeling from cryosections and from high pressure frozen samples has revealed a steep gradient in the distribution of the storage proteins within the Golgi stack. Intense labeling for storage proteins was registered for the cis-cisternae, contrasting with very low labeling for these antigens in the trans-cisternae. The distribution of BP-80 was the reverse, showing a peak in the trans-Golgi network with very low labeling of the cis-cisternae. These results indicate a spatial separation of different vacuolar sorting events in the Golgi apparatus of developing pea cotyledons.

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Trafficking to the seed protein storage vacuole

Functional Plant Biology ◽

10.1071/fp17318 ◽

2018 ◽

Vol 45 (9) ◽

pp. 895

Author(s):

Joanne R. Ashnest ◽

Anthony R. Gendall

Keyword(s):

Storage Proteins ◽

Seed Storage ◽

Seed Storage Proteins ◽

Protein Storage ◽

Protein Storage Vacuole ◽

2S Albumins ◽

Vacuolar Sorting ◽

Mechanistic Understanding ◽

Lytic Vacuole ◽

Storage Vacuole

The processing and subcellular trafficking of seed storage proteins is a critical area of physiological, agricultural and biotechnological research. Trafficking to the lytic vacuole has been extensively discussed in recent years, without substantial distinction from trafficking to the protein storage vacuole (PSV). However, despite some overlap between these pathways, there are several examples of unique processing and machinery in the PSV pathway. Moreover, substantial new data has recently come to light regarding the important players in this pathway, in particular, the intracellular NHX proteins and their role in regulating lumenal pH. In some cases, these new data are limited to genetic evidence, with little mechanistic understanding. As such, the implications of these data in the current paradigm of PSV trafficking is perhaps yet unclear. Although it has generally been assumed that the major classes of storage proteins are trafficked via the same pathway, there is mounting evidence that the 12S globulins and 2S albumins may be trafficked independently. Advances in identification of vacuolar targeting signals, as well as an improved mechanistic understanding of various vacuolar sorting receptors, may reveal the differences in these trafficking pathways.

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Sunflower storage proteins are transported in dense vesicles that contain proteins homologous to the pumpkin vacuolar sorting receptor PV 72

Electronic Journal of Biotechnology ◽

10.2225/vol9-issue3-fulltext-21 ◽

2006 ◽

Vol 9 (3) ◽

pp. 0-0 ◽

Cited By ~ 2

Author(s):

Maria Isabel Molina ◽

Marisa Otegui ◽

Silvana Petruccelli

Keyword(s):

Storage Proteins ◽

Vacuolar Sorting Receptor ◽

Vacuolar Sorting ◽

Sorting Receptor ◽

Dense Vesicles

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The Small GTPase Rab5a Is Essential for Intracellular Transport of Proglutelin from the Golgi Apparatus to the Protein Storage Vacuole and Endosomal Membrane Organization in Developing Rice Endosperm

PLANT PHYSIOLOGY ◽

10.1104/pp.111.180505 ◽

2011 ◽

Vol 157 (2) ◽

pp. 632-644 ◽

Cited By ~ 25

Author(s):

Masako Fukuda ◽

Mio Satoh-Cruz ◽

Liuying Wen ◽

Andrew J. Crofts ◽

Aya Sugino ◽

...

Keyword(s):

Golgi Apparatus ◽

Intracellular Transport ◽

Small Gtpase ◽

Membrane Organization ◽

Rice Endosperm ◽

Protein Storage ◽

Endosomal Membrane ◽

Protein Storage Vacuole ◽

Storage Vacuole

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Vacuolar Storage Proteins and the Putative Vacuolar Sorting Receptor BP-80 Exit the Golgi Apparatus of Developing Pea Cotyledons in Different Transport Vesicles

The Plant Cell ◽

10.1105/tpc.11.8.1509 ◽

1999 ◽

Vol 11 (8) ◽

pp. 1509-1524 ◽

Cited By ~ 79

Author(s):

Giselbert Hinz ◽

Stefan Hillmer ◽

Matthias Bäumer ◽

Inge Hohl

Keyword(s):

Golgi Apparatus ◽

Storage Proteins ◽

Transport Vesicles ◽

Vacuolar Sorting Receptor ◽

Vacuolar Sorting ◽

Sorting Receptor

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The protein storage vacuole

The Journal of Cell Biology ◽

10.1083/jcb.200107012 ◽

2001 ◽

Vol 155 (6) ◽

pp. 991-1002 ◽

Cited By ~ 113

Author(s):

Liwen Jiang ◽

Thomas E. Phillips ◽

Christopher A. Hamm ◽

Yolanda M. Drozdowicz ◽

Philip A. Rea ◽

...

Keyword(s):

Seed Development ◽

Secretory Pathway ◽

Storage Proteins ◽

Plant Seed ◽

Protein Storage ◽

Protein Storage Vacuoles ◽

Protein Storage Vacuole ◽

Membrane Bound ◽

Lytic Vacuole ◽

Storage Vacuole

Storage proteins are deposited into protein storage vacuoles (PSVs) during plant seed development and maturation and stably accumulate to high levels; subsequently, during germination the storage proteins are rapidly degraded to provide nutrients for use by the embryo. Here, we show that a PSV has within it a membrane-bound compartment containing crystals of phytic acid and proteins that are characteristic of a lytic vacuole. This compound organization, a vacuole within a vacuole whereby storage functions are separated from lytic functions, has not been described previously for organelles within the secretory pathway of eukaryotic cells. The partitioning of storage and lytic functions within the same vacuole may reflect the need to keep the functions separate during seed development and maturation and yet provide a ready source of digestive enzymes to initiate degradative processes early in germination.

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