Search results for "Coatomer"
showing 8 items of 8 documents
Loss of
2020
The early secretory pathway involves bidirectional transport between the endoplasmic reticulum (ER) and the Golgi apparatus and is mediated by coat protein complex I (COPI)-coated and coat protein complex II (COPII)-coated vesicles. COPII vesicles are involved in ER to Golgi transport meanwhile COPI vesicles mediate intra-Golgi transport and retrograde transport from the Golgi apparatus to the ER. The key component of COPI vesicles is the coatomer complex, that is composed of seven subunits (α/β/β'/γ/δ/ε/ζ). In Arabidopsis two genes coding for the β-COP subunit have been identified, which are the result of recent tandem duplication. Here we have used a loss-of-function approach to study the…
ß-COP mutants show specific high sensitivity to chloride ions.
2021
Coat Protein I (COPI) consists of a complex (coatomer) formed by seven subunits (α-, β-, β’-, γ-, δ-, ε-, and ζ-COP) that is recruited to Golgi membranes to form vesicles that shuttle from the Golgi apparatus to the ER and between Golgi stacks. Recently, it has been described that loss of function mutants of the two Arabidopsis β-COP genes, β1-COP and β2-COP, showed increased sensitivity to salt stress (NaCl). Using a mixture of either Na(+) or Cl(−) salts, we have now found that β-COP mutants are specifically and highly sensitive to chloride ions.
Targeting COPZ1 non-oncogene addiction counteracts the viability of thyroid tumor cells
2017
Abstract Thyroid carcinoma is generally associated with good prognosis, but no effective treatments are currently available for aggressive forms not cured by standard therapy. To find novel therapeutic targets for this tumor type, we had previously performed a siRNA-based functional screening to identify genes essential for sustaining the oncogenic phenotype of thyroid tumor cells, but not required to the same extent for the viability of normal cells (non-oncogene addiction paradigm). Among those, we found the coatomer protein complex ζ1 (COPZ1) gene, which is involved in intracellular traffic, autophagy and lipid homeostasis. In this paper, we investigated the mechanisms through which COPZ…
alpha 2-COP is involved in early secretory traffic in Arabidopsis and is required for plant growth
2017
[EN] COP (coat protein) I-coated vesicles mediate intra-Golgi transport and retrograde transport from the Golgi to the endoplasmic reticulum. These vesicles form through the action of the small GTPase ADP-ribosylation factor 1 (ARF1) and the COPI heptameric protein complex (coatomer), which consists of seven subunits (alpha-, beta-, beta' -, gamma-, delta-, epsilon- and xi-COP). In contrast to mammals and yeast, several isoforms for coatomer subunits, with the exception of gamma and delta, have been identified in Arabidopsis. To understand the role of COPI proteins in plant biology, we have identified and characterized a loss-of-function mutant of alpha 2-COP, an Arabidopsis alpha-COP isofo…
Functional characterization of Coat Protein I (COPI) subunit isoforms in Arabidopsis thaliana
2022
La vía secretora temprana implica el transporte bidireccional entre el retículo endoplásmico (ER) y el aparato de Golgi y está mediada por vesículas recubiertas del complejo de proteína de cubierta I (COPI) y del complejo de proteína de cubierta II (COPII). Las vesículas COPII están involucradas en el transporte del RE al aparato de Golgi, mientras que las vesículas COPI median el transporte intra-Golgi y el transporte retrógrado desde el aparato de Golgi al RE. El componente clave de la cubierta de COPI es un complejo citoplasmático denominado coatómero, que se compone de siete subunidades (α/β/β’/γ/δ/ε/ζ) y se recluta en bloque desde el citosol hacia las membranas de Golgi. Se ha descrito…
Sorting signals in the cytosolic tail of membrane proteins involved in the interaction with plant ARF1 and coatomer.
2004
Summary In mammals and yeast, a cytosolic dilysine motif is critical for endoplasmic reticulum (ER) localization of type I membrane proteins. Retrograde transport of type I membrane proteins containing dilysine motifs at their cytoplasmic carboxy (C)-terminal tail involves the interaction of these motifs with the COPI coat. The C-terminal dilysine motif has also been shown to confer ER localization to type I membrane proteins in plant cells. Using in vitro binding assays, we have analyzed sorting motifs in the cytosolic tail of membrane proteins, which may be involved in the interaction with components of the COPI coat in plant cells. We show that a dilysine motif in the −3,−4 position (rel…
Characterization of Cop I Coat Proteins in Plant Cells
2000
Membrane traffic in eukaryotic cells is mediated by COP (coat protein)-coated vesicles. Their existence in plant cells has not yet been unequivocally demonstrated, although coated vesicles (probably with a COP coat) can be seen by electron microscopy. At the gene level, plant cells seem to contain all the components necessary to form COP-coated vesicles. In this paper, we have used antibodies raised against mammalian COPI coat proteins to detect putative homologues in rice (Oryza sativa) cells. Using these antibodies, we have found that rice cells contain alpha-, beta-, beta'-, and gamma-COP, as well as ADP-ribosylation factor (ARF) 1 protein. In addition, we show that antibodies against ma…
In vivo Trafficking and Localization of p24 Proteins in Plant Cells
2008
p24 proteins constitute a family of putative cargo receptors that traffic in the early secretory pathway. p24 proteins can be divided into four subfamilies (p23, p24, p25 and p26) by sequence homology. In contrast to mammals and yeast, most plant p24 proteins contain in their cytosolic C-terminus both a dilysine motif in the -3, -4 position and a diaromatic motif in the -7, -8 position. We have previously shown that the cytosolic tail of Arabidopsis p24 proteins has the ability to interact with ARF1 and coatomer (through the dilysine motif) and with COPII subunits (through the diaromatic motif). Here, we establish the localization and trafficking properties of an Arabidopsis thaliana p24 pr…