Eric Whitters - Academia.edu (original) (raw)

Papers by Eric Whitters

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Cell, Feb 22, 1991

SEC14p is the yeast phosphatidylinositol (PI)/phosphatidylcholine (PC) transfer protein, and it e... more SEC14p is the yeast phosphatidylinositol (PI)/phosphatidylcholine (PC) transfer protein, and it effects an essential stimulation of yeast Golgi secretory function. We now report that the SEC14p localizes to the yeast Golgi and that the SEC14p requirement can be specifically and efficiently bypassed by mutations in any one of at least six genes. One of these suppressor genes was the structural gene for yeast choline kinase (CKI), disruption of which rendered the cell independent of the normally essential SEC14p requirement. The antagonistic action of the CKI gene product on SEC14p function revealed a previously unsuspected influence of biosynthetic activities of the CDP-choline pathway for PC biosynthesis on yeast Golgi function and indicated that SEC14p controls the phospholipid content of yeast Golgi membranes in vivo.

Abstract. SEC14p is required for protein transport from the yeast Golgi complex. We describe a qu... more Abstract. SEC14p is required for protein transport from the yeast Golgi complex. We describe a quantitative analysis of yeast bulk membrane and Golgi membrane phospholipid composition under conditions where Golgi secretory function has been uncoupled from its usual SEC14p requirement. The data demonstrate that SEC14p specifically functions to maintain a reduced phosphatidylcholine content in Golgi membranes and indicate that overproduction of SEC14p markedly reduces the apparent rate of phosphatidylcholine biosynthesis via the CDP-choline pathway in vivo. We suggest that SEC14p serves as a sensor of Golgi membrane phospholipid composition through which the activity of the CDP-choline pathway in Golgi membranes is regulated such that a phosphatidylcholine

Journal of Neuropathology and Experimental Neurology, 1985

Journal of Allergy and Clinical Immunology, Feb 1, 2018

The detection of serum-specific IgE (sIgE) is increasingly being used to aid in the diagnosis of ... more The detection of serum-specific IgE (sIgE) is increasingly being used to aid in the diagnosis of an allergy sensitization. However, skin prick tests (SPT) and oral food challenges (OFC) continue to remain the gold standards for confirming allergy diagnosis. The purpose of this study is to determine the correlation between a positive SPT or OFC result and an IgE result obtained on the new system*. METHODS: The system is a fully-automated immunoassay platform to quantify specific IgE concentrations in serum and utilizes magnetic microparticles to which allergens are coupled by a process called ''onboard kitting''. The assay then adds 4 mL of serum to the coated beads in order to quantify sIgE concentrations for that allergen. For this study, remnant de-identified human samples were selected based on a positive skin prick test or oral food challenge to 8 common inhalant allergens and 3 food allergens. RESULTS: For each allergen, 10 to 30 positive SPT or OFC samples were identified and tested on the system (level >0.35 kU/L is considered a positive result). For the 8 inhalant allergens, an average of 76% positive agreement (min: 67%, max: 87%) between SPT and the system was found. For the 3 food allergens, the average was 93% positive agreement (min: 90%, max: 100%) between OFC and the system. CONCLUSIONS: The data demonstrates general agreement with OFC and SPT; this suggests that the new system could be an important tool in the monitoring of allergen sensitivity. *For Investigational Use Only.

Virology, Jun 30, 1990

We report the production and characterization of murine anti-PreS2 and anti-PreSl monoclonal anti... more We report the production and characterization of murine anti-PreS2 and anti-PreSl monoclonal antibodies (mAb) and demonstrate their utility in discriminating hepatitis B virus (HBV) subtypes. On the basis of Western blotting and reciprocal competition binding to HBV virions, at least five distinct epitopes have been identified in the PreS domain: two within the PreSl region and three within the PreS2 region. All PreSP mAb bind M protein (gp33 and gp36) but only one group binds strongly to M and L proteins (p39 and gp42). This group determinant was mapped to peptide residues 120-145. The second group bound to an endoglycosidase F-sensitive epitope which is defined by a mannose-rich glycan at ASN 123 in the PreSP region. The third group was mapped to peptide residues 150-l 74 and was reactive with the M envelope proteins but not L or S proteins on Western blots. All PreSl mAb bind L protein but not M protein on Western blots. Using these mAb, HBV subtype assays were developed allowing evaluation of the Paris (1975) HBsAg subtype panel members along with other HBsAg-positive specimens. All Paris subtype members (except ayw, and ayw,) could be easily distinguished by differential PreS2 mAb reactivity. The Paris subtypes, adw,, adw,, and adr, could be classified as distinct groups by PreS2 and PreSl mAb binding. Specimens from Hong Kong and the United States classified as adw, in the S region fell into two groups based on PreS2 mAb binding: one having reactivity similar to Paris adw, subtype and the other having identical reactivity to Paris ayw, subtype. Furthermore, some specimens classified as adr in the S region gave similar reactivity to the Paris ayr subtype in the PreSP and PreSl regions. One complicating factor in this approach toward subtyping was the discovery that some HBsAg positive sera may contain factors which block PreS epitopes. Grouping of HBV subtypes by PreSl, PreS2, and S mAb reactivity may allow better correlation with groupings based on HBV DNA sequence homology. o 1990Academic PWSS, IN.

The Journal of Cell Biology

SEC14p is required for protein transport from the yeast Golgi complex. We describe a quantitative... more SEC14p is required for protein transport from the yeast Golgi complex. We describe a quantitative analysis of yeast bulk membrane and Golgi membrane phospholipid composition under conditions where Golgi secretory function has been uncoupled from its usual SEC14p requirement. The data demonstrate that SEC14p specifically functions to maintain a reduced phosphatidylcholine content in Golgi membranes and indicate that overproduction of SEC14p markedly reduces the apparent rate of phosphatidylcholine biosynthesis via the CDP-choline pathway in vivo. We suggest that SEC14p serves as a sensor of Golgi membrane phospholipid composition through which the activity of the CDP-choline pathway in Golgi membranes is regulated such that a phosphatidylcholine content that is compatible with the essential secretory function of these membranes is maintained.

Mutations in the SAC1 gene exhibit allelespecific genetic interactions with yeast actin structura... more Mutations in the SAC1 gene exhibit allelespecific genetic interactions with yeast actin structural gene defects and effect a bypass of the cellular requirement for the yeast phosphatidylinositol/phosphatidylcholine transfer protein (SEC14p), a protein whose function is essential for sustained Golgi secretory function. We report that SAClp is an integral membrane protein that localizes to the yeast Golgi complex and to the yeast ER, but does not exhibit a detectable association with the bulk of the yeast F-actin cytoskeleton. The data also indicate that the profound in vivo effects on Golgi secretory function and the organization of the actin cytoskeleton observed in sad mutants result from loss of SAClp function. This cosuppression of actin and SEC14p defects is a unique feature of sad alleles as mutations in other SAC genes that result in a suppression of actin defects do not

Journal of Biological Chemistry, 2012

PLoS ONE, 2020

Background Cross-reactive carbohydrate determinant (CCD) structures found in plant and insect gly... more Background Cross-reactive carbohydrate determinant (CCD) structures found in plant and insect glycoproteins are commonly recognized by IgE antibodies as epitopes that can lead to extensive cross-reactivity and obscure in vitro diagnostic (IVD) serology results. With the introduction of component resolved diagnosis (CRD), recombinant non-glycosylated components have been utilized to mitigate the risk of CCD-specific IgE (sIgE) detection. However, a recent study has shown that CCD-sIgE may bind directly to the cellulose solid phase matrix used in certain in vitro diagnostic assays, eliminating the advantage of CRD over traditional extract-based testing. The aim of this study is to further investigate the prevalence of CCD-sIgE interference on a commonly-used in vitro sIgE automated platform which employs a cellulose-based matrix to immobilize CCD-free recombinant components. Methods Sera from patients sensitized to peanut, silver birch, and/or timothy grass were analyzed for CCD-sIgE ...