Cotranslational Integration of Soybean (Glycine max) Oil Body Membrane Protein Oleosin into Microsomal Membranes

Loer, Deborah S.; Herman, Eliot M.

doi:10.1104/pp.101.3.993

Cited by 65 publications

(57 citation statements)

References 13 publications

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“…This provides preliminary evidence for a cotranslational, signal recognition particle-mediated targeting pathway but does not rule out post-translational ER targeting of oleosins (Ng et al, 1996). No signal sequence cleavage has been observed during microsome translation (Hills et al, 1993;Loer and Herman, 1993), and a noncleaved signal sequence remains unidentified. In this respect, oleosin is unique, because all other characterized seed storage proteins targeted to the ER are known to possess N-terminal cleavable signal sequences (Chrispeels and Raikhel, 1992).…”

Section: Introductionmentioning

confidence: 75%

“…Qu et al (1986) demonstrated that the vast majority of oleosin synthesis is directed by membrane-bound polyribosomes in maize. Subsequent studies showed that in vitrc-translated oleosin could be targeted to canine pancreatic microsomes but not to erythrocytes, plastids, heat-inactivated canine pancreatic microsomes, or oil bodies (Hills et al, 1993;Loer and Herman, 1993). Although these experiments did not demonstrate the pathway of ER targeting, it has been found that the signal recognition particle is capable of causing translational arrest in vitro (Thoyts et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

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Role of the Proline Knot Motif in Oleosin Endoplasmic Reticulum Topology and Oil Body Targeting

Abell¹,

Holbrook²,

Abenes³

et al. 1997

The Plant Cell

105

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An Arabidopsis oleosin was used as a model to study oleosin topology and targeting to oil bodies. Oleosin mRNA was in vitro translated with canine microsomes in a range of truncated forms. This allowed proteinase K mapping of the membrane topology. Oleosin maintains a conformation with a membrane-integrated hydrophobic domain flanked by N-and C-terminal domains located on the outer microsome surface. This is a unique membrane topology on the endoplasmic reticulum (ER). Three universally conserved proline residues within the "proline knot" motif of the oleosin hydrophobic domain were substituted by leucine residues. After in vitro translation, only minor differences in proteinase K protection could be observed. These differences were not apparent in soybean microsomes. No significant difference in incorporation efficiency on the ER was observed between the two oleosin forms. However, as an oleosin-P-glucuronidase translational fusion, the proline knot variant failed to target to oil bodies in both transient embryo expression and in stably transformed seeds. Fractionation of transgenic embryos expressing oleosin-P-glucuronidase fusions showed that the proline knot variant accumulated in the ER to similar levels compared with the native form. Therefore, the proline knot motif is not important for ER integration and the determination of topology but is required for oil body targeting. The loss of the proline knot results in an intrinsic instability in the oleosin polypeptide during trafficking.

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Section: Introductionmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Role of the Proline Knot Motif in Oleosin Endoplasmic Reticulum Topology and Oil Body Targeting

Abell¹,

Holbrook²,

Abenes³

et al. 1997

The Plant Cell

105

View full text Add to dashboard Cite

show abstract

“…There is evidence to suggest that oleosin is co-translationally integrated into rough endoplasmic reticulum (rER) membranes [8,9]. It is also known from biochemical experiments that biogenesis of oil bodies parallels the localisation of oleosins in rER membranes [10,11]. Even though signal sequence for targeting of oleosin to the sites where oil bodies are formed is not known [8,10,12,13] These data indicate that there is dynamic interaction between sites of oil body formation and oleosin synthesis [14,15].…”

Section: Introductionmentioning

confidence: 86%

“…It is also known from biochemical experiments that biogenesis of oil bodies parallels the localisation of oleosins in rER membranes [10,11]. Even though signal sequence for targeting of oleosin to the sites where oil bodies are formed is not known [8,10,12,13] These data indicate that there is dynamic interaction between sites of oil body formation and oleosin synthesis [14,15]. Oleosins are unusual proteins because they possess three different functional domains: a 70-80-residue uninterrupted hydrophobic domain is flanked by relatively polar amino-and carboxy-terminal domains.…”

Section: Introductionmentioning

confidence: 99%

Amino-Terminus of Oleosin Protein Defines the Size of Oil Bodies - Topological Model of Oleosin-Oil Body Complex

J¹,

P²

2015

Saha, J Plant Biochem Physiol

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Lipids formed in seeds of oilseed plant are stored in specific cytosolic structures called oil bodies, which are covered with oleosin proteins. Disruption of oleosin layer by heat treatment makes lipids susceptible to oxidation. By analyzing the amino acid sequence of Arabidopsis oleosin, unique domains were identified within the aminoterminus of the protein. Removal of these domains affected both the size of oil bodies and their susceptibility to lipid-specific stain, Nile Blue A. Amino-terminally truncated oleosin mutant, which was in fusion to green fluorescent protein (GFP), confined to rough endoplasmic reticulum (rER) suggesting that the amino-terminus of oleosin is required for the efficient lateral transportation of oleosin proteins from rER to oil bodies. The size of oil bodies covered by amino-terminal mutants was at least 5 times larger than native oil bodies. Based on the observations, a topological model was generated, which could explain how oleosin maintains and protects the integrity of oil bodies during seed storage. Citation: Wahlroos T, Soukka J, Denesyuk A, Susi P (2015) Amino-Terminus of Oleosin Protein Defines the Size of Oil Bodies -Topological Model of Oleosin-Oil Body Complex. J Plant Biochem Physiol 3: 155. Amino-Terminus of Oleosin

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“…were physically isolated from soymilk (Fujiki et al, 1982;Loer and Herman, 1993). Soymilk (100 mL), Tris (hydroxymethyl) aminomethane ( Additionally, the floating layer was diluted in the 1.0% lipid soymilk.…”

Section: Isolation Of Oil Bodies and Sample Preparation Oil Bodiesmentioning

confidence: 99%

Rheological Analysis of the Aggregation Behavior of a Soymilk Colloidal System

Idogawa

Fujii

2015

FSTR

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The applicability of Einstein's and Krieger-Dougherty's theories of viscosity was examined using soymilk. Under dilute conditions, the relative viscosity of the emulsion with suspended oil bodies was proportional to the volume fraction of oil bodies, and the slope increased to greater than 2.5. Under concentrated conditions, the oil body suspension showed a Krieger-Dougherty-like dependency on volume fraction. The oil bodies in soymilk behaved as suspended substances and it was possible for us to predict the relative viscosity from the volume fraction of oil bodies. We also focused on the coagulation of soymilk by magnesium chloride and examined the validity of the novel viscous model, combining the extended Einstein equation and the Krieger-Dougherty equation, on the effect of crosslinkers. At 10℃ and 25℃, the equation could be applied to various soymilk samples. In addition, the viscosity during coagulation could be predicted when the parameter h c of the dispersion system was utilized.Keywords: soymilk, einstein, Krieger-Dougherty, rheology, oil body, suspension IntroductionSoymilk production has increased because of the heightened consumer interest in the functionality of this protein-laden beverage.There has been a significant amount of research published about soybean proteins (Mori et al., 1986;Thanh and Shibasaki, 1977;Yuan et al., 2009) and soybean protein isolates as new food materials (Campbell et al., 2009;Fukushima, 2001). However, very little information about the physicochemical properties of soymilk is available (Nik et al., 2008;Nsofor and Osuji, 1997;Ringgenberg et al., 2012). Understanding the physicochemical properties of soymilk, including viscosity, is required in the development of soymilk products. Viscosity equations were developed in order to predict viscosity in colloidal food systems. Viscosity is a physical property that can be effectively utilized in characterizing the effect of quality control of a manufacturing process or mechanical and thermal processing. Soymilk is a colloidal system produced as an extract from swelled and ground soybeans; therefore, almost all of the components (protein, lipid, and saccharides) of the soybean seeds are present in the soymilk (Shurtleff and Aoyagi, 2000). It was reported that about 70% of the lipids in soybeans were extracted to the soymilk (Poysa and Woodrow, 2002). Dispersed substances consist of oil bodies and protein particles and the dispersion medium is the liquid containing the dissolved proteins, sugars, and minerals such as potassium. Oil bodies consist of a triacylglycerol (TAG) matrix core surrounded by a layer of phospholipids and intrinsic oleosin (Li et al., 2001;Tzen and Huang, 1992). The average particle diameter of an oil body in soymilk is approx. 250 nm (Iwanaga et al., 2007). Oil bodies containing soymilk lipids were stabilized by the presence of oleosin and phospholipids on their surface (Chen and Ono, 2010).Einstein developed a theory for the viscosity of a dilute suspension of small hard spheres in a continuous fluid (Eins...

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Cotranslational Integration of Soybean (Glycine max) Oil Body Membrane Protein Oleosin into Microsomal Membranes

Cited by 65 publications

References 13 publications

Role of the Proline Knot Motif in Oleosin Endoplasmic Reticulum Topology and Oil Body Targeting

Role of the Proline Knot Motif in Oleosin Endoplasmic Reticulum Topology and Oil Body Targeting

Amino-Terminus of Oleosin Protein Defines the Size of Oil Bodies - Topological Model of Oleosin-Oil Body Complex

Rheological Analysis of the Aggregation Behavior of a Soymilk Colloidal System

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