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Protein Sorting to the Storage Vacuoles of Plants: A Critical Appraisal
Author(s) -
Robinson David G.,
Oliviusson Peter,
Hinz Giselbert
Publication year - 2005
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2005.00303.x
Subject(s) - biology , vacuole , golgi apparatus , microbiology and biotechnology , context (archaeology) , protein targeting , storage protein , secretory pathway , endosome , receptor , proteome , transport protein , biochemistry , membrane protein , intracellular , endoplasmic reticulum , cytoplasm , gene , membrane , paleontology
The vacuole of plant cells is no longer considered to be a single compartment with multifunctional properties. A lot of evidence now points to the presence of multiple functionally distinct vacuolar compartments, some existing side by side in the same cell. As a consequence, the plant Golgi apparatus is faced with the problem of recognizing proteins destined for lytic and storage vacuoles and segregating them individually from the flow of secretory proteins to the cell surface. In contrast to acid hydrolases, which are sorted by BP‐80‐like receptors at the trans ‐Golgi of plant cells, the identification of receptors for storage proteins has in many ways resembled ‘the search for the Holy Grail’. There are several candidates for storage protein receptors, but in no single case is the evidence entirely convincing. Much of the problem lies in the lack of consensus, sorting sequences in the proteins investigated. Other difficulties stem from ‘out‐of‐context’ heterologous expression studies. Evidence is now accumulating for the participation of hydrophobic sequences in inducing the formation of protein aggregates in the early Golgi apparatus, for which classical sorting receptors do not appear to be necessary. This review critically examines the current situation and contrasts the differences between data obtained in situ and data obtained transgenically. It highlights the so‐called ‘dense‐vesicle’ pathway and culminates with a discussion on the hitherto neglected problem of the intracellular transport of storage protein processing enzymes.