Binding of BiP to an assembly‐defective protein in plant cells

Giovinazzo, Giovanna; Bollini, Roberto; Ceriotti, Aldo; Vitale, Alessandro

doi:10.1046/j.1365-313x.1994.5010103.x

Cited by 77 publications

(62 citation statements)

References 21 publications

(40 reference statements)

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“…6A, lane 1). Like the other members of the heat shock 70 class of chaperones, BiP has ATPase activity and can be released from its bound ligands by ATP treatment (Munro and Pelham 1986; for experiments on phaseolin, see Pedrazzini et al, 1994Pedrazzini et al, , 1997Vitale et al, 1995). When the immunoprecipitate was treated with ATP, the 78-kD polypeptide was released and could be immunoselected with anti-BiP antiserum, confirming it was BiP (Fig.…”

Section: Zeolin Has Slow Turnover and Long-lasting Interactions With Bipmentioning

confidence: 78%

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Zeolin. A New Recombinant Storage Protein Constructed Using Maize γ-Zein and Bean Phaseolin

et al. 2004

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The major seed storage proteins of maize (Zea mays) and bean (Phaseolus vulgaris), zein and phaseolin, accumulate in the endoplasmic reticulum (ER) and in storage vacuoles, respectively. We show here that a chimeric protein composed of phaseolin and 89 amino acids of γ-zein, including the repeated and the Pro-rich domains, maintains the main characteristics of wild-type γ-zein: It is insoluble unless its disulfide bonds are reduced and forms ER-located protein bodies. Unlike wild-type phaseolin, the protein, which we called zeolin, accumulates to very high amounts in leaves of transgenic tobacco (Nicotiana tabacum). A relevant proportion of the ER chaperone BiP is associated with zeolin protein bodies in an ATP-sensitive fashion. Pulse-chase labeling confirms the high affinity of BiP to insoluble zeolin but indicates that, unlike structurally defective proteins that also extensively interact with BiP, zeolin is highly stable. We conclude that the γ-zein portion is sufficient to induce the formation of protein bodies also when fused to another protein. Because the storage proteins of cereals and legumes nutritionally complement each other, zeolin can be used as a starting point to produce nutritionally balanced and highly stable chimeric storage proteins.

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Section: Zeolin Has Slow Turnover and Long-lasting Interactions With Bipmentioning

confidence: 78%

“…For pulse-chase labeling, protoplasts were prepared from transgenic plants as described by Pedrazzini et al (1994) and subjected to pulse-chase radioactive labeling in the absence or presence of brefeldin A (Roche) as described by Pedrazzini et al (1997).…”

Section: Protein Analysismentioning

confidence: 99%

Zeolin. A New Recombinant Storage Protein Constructed Using Maize γ-Zein and Bean Phaseolin

et al. 2004

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“…Moreover, truncated ␥-zeins containing the N-terminal proline-rich domain were sorted and retained in the ER inside the transformed leaf cells (10). These results contrast with what frequently occurs when other truncated proteins are overexpressed; they usually associate with BiP and are ultimately degraded in lytic vacuoles (19,20) or enter the ER-associated protein degradation (ERAD) pathway (21,22). The proline-rich N-terminal sequence of ␥-zein comprising the first 112 amino…”

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confidence: 84%

Relevant Elements of a Maize γ-Zein Domain Involved in Protein Body Biogenesis

Llop‐Tous

Madurga

Giralt

et al. 2010

Journal of Biological Chemistry

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The N-terminal proline-rich domain of ␥-zein (Zera) plays an important role in protein body (PB) formation not only in the original host (maize seeds) but in a broad spectrum of eukaryotic cells. However, the elements within the Zera sequence that are involved in the biogenesis of PBs have not been clearly identified. Here, we focused on amino acid sequence motifs that could be involved in Zera oligomerization, leading to PB-like structures in Nicotiana benthamiana leaves. By using fusions of Zera with fluorescent proteins, we found that the lack of the repeat region (PPPVHL) 8 of Zera resulted in the secretion of the fusion protein but that this repeat by itself did not form PBs. Although the repeat region containing eight units was the most efficient for Zera self-assembly, shorter repeats of 4 -6 units still formed small multimers. Based on site-directed mutagenesis of Zera cysteine residues and analysis of multimer formation, we conclude that the two N-terminal Cys residues of Zera (Cys 7 and Cys 9 ) are critical for oligomerization. Immunoelectron microscopy and confocal studies on PB development over time revealed that early, small, Zera-derived oligomers were sequestered in buds along the rough ER and that the mature size of the PBs could be attained by both cross-linking of preformed multimers and the incorporation of new chains of Zera fusions synthesized by active membrane-bound ribosomes. Based on these results and on the behavior of the Zera structure determined by molecular dynamics simulation studies, we propose a model of Zera-induced PB biogenesis.The mechanisms by which prolamins, which lack the ER 3 retention (H/K)DEL motif, are retained and assembled in the ER-derived PBs are only partially understood. Different factors act as determinants of PB biogenesis, some of them derived from cis-cargo properties and others with a cellular trans-origin (1). It has been proposed that the physico-chemical properties of prolamins, such as hydrophobicity and disulfide bond formation, promote specific interactions resulting in the formation of large self-assemblies that are responsible for their retention in the ER and PB formation (2-4). These polymers could be excluded because of their size from being carried by the COP II vesicles that transport cargo proteins to the Golgi complex (5). However, the generic COPII vesicles are flexible enough for large cargo loading, including that of procollagen (more than 300 nm in size) (6) and the collagen VII trimer (900 kDa) (7).In maize, four distinct types of prolamins (␣-, ␤-, ␥-, and ␦-zein) coexist in the PBs (8) and play distinct roles in PB formation. Recently, maize storage protein mutants created through RNAi showed that ␥-RNAi maize mutant lines exhibited slightly altered protein body formation and that a more drastic effect was observed in the ␤-␥ combined mutant, where protein bodies showed an irregular shape, particularly in their periphery (9).Various studies on zein accumulation in heterologous expression systems suggest that ␥-zein and ␤-zein mediate t...

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“…Petit Havana SR1. Protoplasts were subjected to polyethylene glycol-mediated transfection as described (30). The agrobacterium containing RTA E177D was used to produce transgenic plants as described (21).…”

Section: Transient Transformation Of Leaf Protoplasts and Production mentioning

confidence: 99%

Ricin A chain without its partner B chain is degraded after retrotranslocation from the endoplasmic reticulum to the cytosol in plant cells

Cola

Frigerio

Lord

et al. 2001

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

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When expressed in tobacco cells, the catalytic subunit of the dimeric ribosome inactivating protein, ricin, is first inserted into the endoplasmic reticulum (ER) and then degraded in a manner that can be partially inhibited by the proteasome inhibitor clastolactacystin ␤-lactone. Consistent with the implication of cytosolic proteasomes, degradation of ricin A chain is brefeldin A-insensitive and the polypeptides that accumulate in the presence of the proteasome inhibitor are not processed in a vacuole-specific fashion. Rather, these stabilized polypeptides are in part deglycosylated by a peptide:N-glycanase-like activity. Taken together, these results indicate that ricin A chain, albeit a structurally native protein, can behave as a substrate for ER to cytosol export, deglycosylation in the cytosol, and proteasomal degradation. Furthermore, retrotranslocation of this protein is not tightly coupled to proteasomal activity. These data are consistent with the hypothesis that ricin A chain can exploit the ER-associated protein degradation pathway to reach the cytosol. Although well characterized in mammalian and yeast cells, the operation of a similar pathway to the cytosol of plant cells has not previously been demonstrated.

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Binding of BiP to an assembly‐defective protein in plant cells

Cited by 77 publications

References 21 publications

Zeolin. A New Recombinant Storage Protein Constructed Using Maize γ-Zein and Bean Phaseolin

Zeolin. A New Recombinant Storage Protein Constructed Using Maize γ-Zein and Bean Phaseolin

Relevant Elements of a Maize γ-Zein Domain Involved in Protein Body Biogenesis

Ricin A chain without its partner B chain is degraded after retrotranslocation from the endoplasmic reticulum to the cytosol in plant cells

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