Jeffrey I. McCormick

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Injection of mRNA from GF-14 cells (a mouse lymphocyte cell line) into Xenopus oocytes led to the expression of a transport activity characteristic of amino acid transport system A, i.e., Na+ dependent and recognizing aminoisobutyric acid and its methyl derivative (AIB and meAIB). Sucrose density gradient fractionation of GF-14 mRNA showed that the maximum(More)
A reconstitution assay was used to measure transport activity during purification of a Na+-dependent amino acid transporter from Ehrlich cell plasma membrane. Cholate/urea-solubilized membranes were fractionated on a Sepharose 6B column and transport activity was recovered in the column void volume. Centrifugation of the void volume fraction at 105,000 X g(More)
Plasma membrane suspensions of Ehrlich ascites cells solubilized with cholic acid were used to study the effects of sulfhydryl reagents on Na(+)-dependent amino acid transport. These suspensions were treated with the sulfhydryl binding agents p-chloromercuribenzenesulfonic acid or N-ethylmaleimide prior to reconstitution for the assay of transport activity.(More)
We have previously reported [McCormick and Johnstone (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 7877-7881] the partial purification of the Na(+)-dependent A-system amino acid transporter from Ehrlich cell plasma membranes and have suggested that a 120-130 kDa peptide, a major component of the purified fraction [octyl glucoside (OG) extract], is involved in(More)
Solubilized Ehrlich cell plasma membrane proteins were incorporated into lipid vesicles in the presence of added phospholipid, using Sephadex G-50 chromatography combined with a freeze-thaw step. Liposomes formed in K+ exhibited high levels of Na+-dependent, alpha-aminoisobutyric acid uptake which was electrogenic and inhibited by other amino acids. The(More)
Radiation inactivation was used to estimate the molecular size of a Na(+)-dependent amino acid transport system in Ehrlich ascites cell plasma membrane vesicles. Na(+)-dependent alpha-aminoisobutyric acid uptake was measured after membranes were irradiated at -78.5 degrees C in a cryoprotective medium. Twenty-five percent of the transport activity was lost(More)
We report here the isolation of two new monoclonal antibodies (MB1.1 and MB1.2) against mouse VLA-beta 1 integrin subunit. Characterization by flow cytometry demonstrated binding of MB1.1 and MB1.2 to freshly isolated thymocytes, primary bone marrow mast cell lines, as well as cell lines of distinct lineage each expressing different combination of VLA(More)
Na+-dependent amino acid transport can be reconstituted from solubilized Ehrlich cell plasma membranes by addition of asolectin vesicles, gel filtration, and a freeze-thaw cycle. Removal of phosphatidic acid (approximately 10% of the total lipid) by Ba2+ precipitation reduces the efficiency of reconstitution of Na+-dependent amino acid transport by(More)
Regrowth of dual-purpose canola after grazing is important for commercial success and the aim of this research was to investigate the effects of defoliation on the development, growth, photosynthesis and allocation of carbohydrates. We conducted two pot experiments in which defoliation was conducted at multiple intensities with scissors. Experiment 1(More)