High-pressure light scattering study of Artemia salina ribosomes and polysomes

Nieuwenhuysen, Paul; Heremans, Karel; Clauwaert, J.

doi:10.1016/0005-2787(80)90039-8

Cited by 8 publications

(8 citation statements)

References 30 publications

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“…Under some conditions, aggregation of both the subunits and 80S particles was found to occur. Aggregation by eucaryotic ribosomes has been reported by others (Nieuwenhuysen & Clauwaert, 1981;Nieuwenhuysen et al, 1980). We found this particularly to be a problem if Mg2+ was greater than 9 mM (see Figure 1) and at low temperature and low figure 2: Equilibria between 80S ribosomes and subunits.…”

Section: Resultssupporting

confidence: 72%

“…Conformational changes have been reported to occur in both E. coli and wheat germ ribosomal subunits (Chaires et al, 1977;Nieuwenhuysen et al, 1980;Bonnert et al, 1980;Moore & Spremulli, 1985). We have not considered conformational transitions in fitting these reactions, but since the association process is second order, such transitions cannot be the ratelimiting step for association.…”

Section: Discussionmentioning

confidence: 99%

“…Electron microscopy (Lake et al, 1974;Boublik & Heilman, 1978) and other physical techniques Nieuwenhuysen et al, 1980) suggested 0006-2960/ 86/0425-3690$01.50/0 © 1986 American Chemical Society general similarity between eucaryotic and procaryotic ribosomes. The composition of eucaryotic and procaryotic ribosomes are similar with eucaryotic ribosomes having larger rRNA (28S, 18S, and 5.8S compared to 23S, 16S, and 5S)…”

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confidence: 99%

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Magnesium ion-dependent equilibria kinetics and thermodynamic parameters of Artemia ribosome dissociation and subunit association

Goss¹,

Harrigan²

1986

Biochemistry

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The influence of magnesium ion concentration on the equilibrium and kinetics of Artemia ribosome dissociation and subunit association has been studied by laser light scattering. Ribosomal aggregation was found to be reduced by addition of 0.1-0.05 mM spermidine and KCl concentrations of 100 mM. The ribosomes were found to be stable at low [Mg2+], and the curves obtained for ribosome-subunit equilibrium were independent of the direction and origin of the magnesium ion titration. Thermodynamic parameters were obtained from the temperature-dependent equilibria and have been compared to those of wheat germ and Escherichia coli type A ribosomes. The entropy term calculated for the association of 40S and 60S subunits is small, and the reaction is exothermic. The entropy term is negative, favoring subunit dissociation, and contributes less to the free energy than the enthalpy term. Rate constants for ribosome dissociation and subunit association have been determined. The reaction curves gave no evidence for sequential processes and were homogeneous.

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Section: Resultssupporting

confidence: 72%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Magnesium ion-dependent equilibria kinetics and thermodynamic parameters of Artemia ribosome dissociation and subunit association

Goss¹,

Harrigan²

1986

Biochemistry

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“…Nieuwenhuysen et al (1980), using Artemia salina ribosomes, have shown that the molar volume changes produced by ribosomal subunit association are similar to those observed with E. coli type A ribosomes. Furthermore, they have suggested that this large volume change is consistent with two fFrom the Departments of Biochemistry (J.M.S.)…”

supporting

confidence: 54%

Influence of various cations on the equilibriums between wheat germ ribosomes and their subunits

Sperrazza¹,

Moore²,

Spremulli³

1981

Biochemistry

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The influence of alkaline earth metal ions, alkali metal ions, ammonium ions, and polyamines upon the equilibria between high-salt-washed wheat germ ribosomes and their subunits was investigated by light scattering. The Mgz+-dependent, reversible association of ribosomal subunits was studied with buffers containing 100 mM concentrations of the chloride salts of various monovalent cations. These studies indicate that K+ and Na+ are most effective in dissociating the ribosomes into subunits, followed by Rb+ and then NH4+. The dissociation curves determined with buffers containing K+, Na', Rb', and NH4+ ions exhibit [Mg"] 1/2 values of 1.4, 1.4, 1.2, and 0.7 mM, respectively. The divalent cations, in general, strongly promote subunit association but differ in their abilities to do so. Ca2+ associates the ribosomal subunits more effectively than Sr2+, which is more effective than Mgz+. In the presence of 100 mM KCl and 0.15 mM MgClz, Ca2+-, Sr2+-, and Mgz+-dependent association curvesx e subunits of both eucaryotic and procaryotic ribosomes are capable of reversible association and dissociation. The types and concentrations of various cations present play a major role in determining the position of the equilibrium between the intact ribosome and its subunits. Kinetic, thermodynamic, and ion-specificity studies have been performed with Escherichia coli ribosomes in an effort to explain the roles of MgZ+, K+, and polyamines in the association of the subunits. Conflicting mechanisms have been proposed as a result of these studies. One model suggests that Mgz+ binds to specific sites on the subunits and thereby promotes subunit association (Petermann, 1964;Goldberg, 1966). This model is supported by the data of Zitomer & Flab (1972), who found that MgZ+, Ca2+, and polyamines promote ribosomal subunit association while K+ promotes subunit dissociation. Ca2+, however, was less effective than Mg2+ in promoting subunit association, suggesting that the ions were acting at specific sites. In contrast, the electrostatic model suggests that Mg2+ neutralizes the charged groups on the ribosomal subunits. This reduction in the electrostatic repulsion between the subunits would allow association. The studies of Walters & Van Os (1970, 1971) on yeast ribosomes and Wishnia & Boussert (1977) on E . coli ribosomes support the electrostatic model. Calculations by these groups also showed that the reduction of the electrostatic repulsion by Mg2+ theoretically is sufficient to promote subunit association. Nieuwenhuysen et al. (1980), using Artemia salina ribosomes, have shown that the molar volume changes produced by ribosomal subunit association are similar to those observed with E. coli type A ribosomes. Furthermore, they have suggested that this large volume change is consistent with two From the exhibit [M2+lIl2 values of 0.9, 1.1, and 1.4 mM, respectively. The abilities of the polyamines to associate ribosomal subunits in buffers containing 100 mM KCl and 0.20 mM MgClz were investigated. Both spermine ( [~p m ]~/~ = 0.09 mM) and sp...

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“…Typically, the internal volume of an exosomes ranges between 20 and 90 nm 3 , resulting in a potential cargo volume of 4.2–380 yoctoliters. ( 10 , 18 ) This internal volume is comparable to the size of a ribosome complex, suggesting that exosomes could contain roughly 100 proteins and 10 000 nucleotides of nucleic acid. ( 10 )…”

Section: Exosomes: Definitions and Biogenesismentioning

confidence: 98%

Exosome proteomics reveals transcriptional regulator proteins with potential to mediate downstream pathways

et al. 2014

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Exosomes are virus-sized, membrane-enclosed vesicles with origins in the cellular endosomal system, but are released extracellularly. As a population, these tiny vesicles carry relatively enormous amounts of information in their protein, lipid and nucleic acid content, and the vesicles can have profound impacts on recipient cells. This review employs publically-available data combined with gene ontology applications to propose a novel concept, that exosomes transport transcriptional and translational machinery that may have direct impacts on gene expression in recipient cells. Here, we examine the previously published proteomic contents of medulloblastoma-derived exosomes, focusing on transcriptional regulators; we found that there are numerous proteins that may have potential roles in transcriptional and translational regulation with putative influence on downstream, cancer-related pathways. We expanded this search to all of the proteins in the Vesiclepedia database; using gene ontology approaches, we see that these regulatory factors are implicated in many of the processes involved in cancer initiation and progression. This information suggests that some of the effects of exosomes on recipient cells may be due to the delivery of protein factors that can directly and fundamentally change the transcriptional landscape of the cells. Within a tumor environment, this has potential to tilt the advantage towards the cancer.

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High-pressure light scattering study of Artemia salina ribosomes and polysomes

Cited by 8 publications

References 30 publications

Magnesium ion-dependent equilibria kinetics and thermodynamic parameters of Artemia ribosome dissociation and subunit association

Magnesium ion-dependent equilibria kinetics and thermodynamic parameters of Artemia ribosome dissociation and subunit association

Influence of various cations on the equilibriums between wheat germ ribosomes and their subunits

Exosome proteomics reveals transcriptional regulator proteins with potential to mediate downstream pathways

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