Phosphatidylinositol transfer activity in rat cerebral hemispheres during development

Brophy, Peter; Aitken, Jane

doi:10.1111/j.1471-4159.1979.tb11741.x

Cited by 22 publications

(5 citation statements)

References 12 publications

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“…We as yet do not know whether the factors that regulate the transfer activity in vitro are relevant to intracellular phospholipid transport. Recent studies, however, do suggest that in vivo there may be a relationship between phospholipid exchange activity and the ability of the cell to synthesize phospholipids or generate membranes (Engle et al, 1978;Brophy & Aitken, 1979).…”

Section: Discussionmentioning

confidence: 99%

Phosphatidylcholine exchange protein catalyzes the net transfer of phosphatidylcholine to model membranes

Wirtz¹,

Devaux²,

Bienvenüe³

1980

Biochemistry

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2-Stearoyl spin-labeled phosphatidylcholine (PC*) has been introduced into the phosphatidylcholine exchange protein from bovine liver and its electron spin resonance (ESR) spectrum determined. The spin-labeled group in the PC*- exchange protein complex was strongly immobilized. Addition of sodium deoxycholate micelles released PC* from its binding site, producing a mobile signal. This was also observed when micelles of lysophosphatidylcholine and vesicles of phosphatidic acid were added, indicating that the exchange protein can insert its endogenous PC* into interfaces devoid of phosphatidylcholine. ESR spectroscopy was used to measure transfer of PC* from spin-labeled "donor" vesicles to unlabeled "acceptor" vesicles as described by Machida & Ohnishi [Machida, K., & Ohnishi, S. (1978) Biochim. Biophys. Acta 507, 156-164]. The donor vesicles consisted of PC* and phosphatidic acid (75:25 mol%) and the acceptor vesicles of phosphatidylethanolamine and phosphatidic acid (81:19 mol%). Addition of exchange protein catalyzed a net transfer of PC* from donor to acceptor vesicles. This transfer proceeded until the acceptor vesicles contained approximately 2 mol% of PC*. A spontaneous transfer of PC* was not observed. As for the mode of action, it appears that the exchange protein, after insertion of its endogenous PC* into the acceptor, leaves the interface without a bound phospholipid molecule yet continues to shuttle PC* from donor to acceptor.

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Section: Discussionmentioning

confidence: 99%

Phosphatidylcholine exchange protein catalyzes the net transfer of phosphatidylcholine to model membranes

Wirtz¹,

Devaux²,

Bienvenüe³

1980

Biochemistry

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“…In studies on the physiological role of these proteins a number of observations have been made which suggest a relationship between the activity of these proteins and certain aspects of meinbrane development and phospholipid composition. An increase of phosphatidylinositol-transfer activity was observed in rat brain which coincided with the onset of myelination [ 13,141. Phosphatidylcholinetransfer activities have been found to correlate with the demand for lung surfactant dipalmitoylphosphatidylcholine [ 15,161.…”

Section: Introductionmentioning

confidence: 90%

Tissue distribution and subcellular localization of phosphatidylcholine transfer protein in rats as determined by radioimmunoassay

Teerlink

Krift

Post

et al. 1982

Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metaboli

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A radioimmunoassay for the phosphatidylcholine-transfer protein from rat liver was used to measure levels of PC-transfer protein in rat tissues. The assay as described before (Tee&k, T., Poorthuis, B.J.H.M., Van der Krift, T.P. and Wirtz, K.W.A., Biochim. Biophys. Acta 665 (1981) 74-80) was modified in order to measure PC-transfer protein in tissue homogenates and subcellular membrane fractions. To this end both a detergent (Triton X-100) and a proteolytic enzyme inhibitor (aprotinin) were added to the assay medium. The radioimmunoassay measured levels of PC-transfer protein in the range of 5-50 ng and was specific for PC-transfer protein from rat tissues. Subcellular distribution studies showed that in 10% (w/v) homogenates of liver approximately 60% of the PC-transfer protein was present in the 105000X g supernatant fraction, the remainder being evenly distributed over the particulate fractions. PC-transfer protein associated with the particulate fractions was almost completely removed by a single washing step, suggesting a dynamic equilibrium between membrane-bound and soluble PC-transfer protein. Both 105000X g supematants and homogenates of various rat tissues were assayed. The highest levels of PC-transfer protein were measured in liver and intestinal mucosa. Lower values were found in kidney, spleen and lung, whereas heart and brain contained hardly any PC-transfer protein. PC-transfer protein levels in regenerating rat liver did not differ significantly from levels in normal liver. In fetal lung a change in PC-transfer protein content during development was observed, with a clear maximum 2 days before term, suggesting an involvement of PC-transfer protein in the secretion of lung surfactant.

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“…The phosphatidylinositol that is synthesized in the endoplasmic reticulum of eukaryotic cells can be transferred to other cellular membranes by phospholipid-exchange proteins residing in the cytoplasm (Helmkamp et ai., 1976;Brophy et ai., 1978;Brophy and Aitken, 1979). In many tissues, phosphatidylinositol is converted by stepwise phosphorylation to the polyphosphoinositides (Kai and Hawthorne, 1969;Tou et ai., 1970;Cooper and Hawthorne, 1976) which occur as very minor constituents of the cellular phospholipid pool.…”

Section: Incorporation Into Phospholipidmentioning

confidence: 99%

The Nutritional Significance, Metabolism, and Function of myo-Inositol and Phosphatidylinositol in Health and Disease

Holub

1982

Advances in Nutritional Research

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Phosphatidylinositol transfer activity in rat cerebral hemispheres during development

Cited by 22 publications

References 12 publications

Phosphatidylcholine exchange protein catalyzes the net transfer of phosphatidylcholine to model membranes

Phosphatidylcholine exchange protein catalyzes the net transfer of phosphatidylcholine to model membranes

Tissue distribution and subcellular localization of phosphatidylcholine transfer protein in rats as determined by radioimmunoassay

The Nutritional Significance, Metabolism, and Function of myo-Inositol and Phosphatidylinositol in Health and Disease

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