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S R Goodman

Publications and source records attributed to S R Goodman.

104 records · Page 6Linked to original sources
PubMed1981

Identification of a spectrin-like protein in nonerythroid cells.

We have demonstrated the existence of a spectrin-like protein in a variety of nonerythroid cultured cells. Indirect immunofluorescence studies with monospecific antispectrin IgG indicated the presence of proteins that have common antigenic determinants to spectrin in embryonic chicken cardiac myocytes, mouse fibroblast lines (3T3, simian virus 4-transformed 3T3), and rat hepatoma lines (HTC, HMOA). Two spectrin-like peptides of 240,000 and 230,000 daltons were immunoprecipitated from octyl glucoside-solubilized embryonic chicken cardiac myocytes, along with associated cytoskeletal proteins. Immunoautoradiographic characterization of the myocyte immunoprecipitate showed that only the spectrin-like 240,000- and 230,000-dalton peptides were stained with monospecific antispectrin IgG and 125I-labeled protein A. One-dimensional partial proteolytic mapping of the myocyte 240,000- and 230,000-dalton peptides showed that these peptides share substantial sequence homology with embryonic chicken erythrocyte spectrin 240,000- and 220,000-dalton peptides.

Animals↗
PubMed1980

The effect of endogenous proteases on the spectrin binding proteins of human erythrocytes.

We have demonstrated that in human erythrocyte ghosts endogenous proteolytic activity is responsible for the digestion of the spectrin binding proteins (bands 2.1 to 2.6). The pH optimum, cofactor requirements and inhibitor sensitivity have been established. Our results indicate that proteolysis of bands 2.1 to 2.6 and the formation of 3', a fragment containing an active spectrin binding site, can occur through two enzymatic pathways: a cascade of consecutive proteolytic cleavages of the spectrin binding proteins inhibited by phenylmethylsulfonyl fluoride or a Ca2+-stimulated, phenylmethylsulfonyl fluoride-insensitive, EDTA-inhibited cleavage of band 2.1 to band 2.3, followed by digestion to band 3' by phenylmethylsulfonyl fluoride-inhibitable enzymes. These findings may provide the techniques necessary to prevent proteolysis of the spectrin binding proteins during purification and reconstitution experiments and provide insight into how they are formed in vivo.

Calcium↗
PubMed1979

Syndeins: the spectrin-binding protein(s) of the human erythrocyte membrane.

Two-dimensional tryptic and chymotryptic analyses of all the major bands in a sodium dodecyl sulfate/polyacrylamide gel of the human erythrocyte membrane show that each band has a characteristic map. However, band 2.1 (nomenclature of T. L. Steck) and several polypeptides below this band exhibit similar tryptic and chymotryptic peptide maps and thus appear to be a family of closely related proteins or degradation products. Furthermore, they all contain a subset of peptides that are accounted for by the peptides from two known spectrin-binding fragments. We show that both fragments derive from 2.1-related proteins and conclude that band 2.1 and its related proteins, which we name "syndeins", bind spectrin and connect it to the erythrocyte membrane.

Carrier Proteins↗
PubMed1978

Two Epstein-Barr virus-associated DNA polymerase activities.

We have partially purified and characterized two separate DNA polymerase activities associated with Epstein-Barr virus (EB virus). One activity is present in EB virus producer cell lines but not in nonproducer or negative cell lines. It adheres more strongly to DEAE-cellulose than any host cell enzymes, eluting at 210 to 270 mM potassium phosphate buffer. Further elution from phosphocellulose and sedimentation in glycerol gradients yields an enzyme purified 900-fold with an S value of 8.3. The second DNA polymerase activity co-purifies with EB viral particles, elutes at low salt from DEAE-cellulose (40 to 60 mM potassium phosphate buffer) and phosphocellulose (100 mM), and has an S value of 9.5 on glycerol gradient sedimentation. These two enzymes are referred to for convenience as the EB virus-induced DNA polymerase and the EB virion-associated DNA polymerase. The EB virus-induced polymerase can be distinguished from host alpha, beta, and the virion-associated polymerase in 1) being resistant to salt inhibition, 2) having a more basic pH optima in Tris buffer (pH 9.5), and 3) having a 10-fold lower saturating concentration for the activated DNA template. The EB virion-associated polymerase is distinguished from host alpha, beta, and the EB virus-induced polymerase, because it cannot utilize synthetic deoxy- and ribohomopolymer primer-templates in place of the activated calf thymus DNA template in DNA polymerase assays. Neither of the EB virus-associated polymerases can copy the ribohomopolymers dT10poly(rA) or dG12-18(poly(rC) efficiently and therefore can be distinguished from host gamma polymerase and reverse transcriptase. The activity of the EB virus-induced and virion-associated polymerases are unaffected both by antibody to alpha polymerase, and by antiserum with high antibody titers to EB early antigen and viral capsid antigen.

Antigen-Antibody Reactions↗
PubMed1978

Spectrin binding and the control of membrane protein mobility.

Transmembrane proteins of the human erythrocyte show restricted in-plane mobility. Many of the restrictions on mobility are attributable to the molecules of spectrin which are located on the protoplasmic surface of the erythrocyte membrane. These molecules are elongate, form end-to-end heterodimer associations, and bind selectively to protein (or proteins) accessible on inside-out, but not right-side out, membrane vesicles.

Actins↗
PubMed1978

Identification and partial purification of two EBV-associated DNA polymerases.

Virally induced DNA polymerases have been demonstrated in cells infected with a variety of herpesviruses. These include herpes simplex virus (Weissbach et al., 1973), Marek's disease virus (Boezi et al., 1974), equine herpesvirus (Allen et al., 1977), and cytomegalovirus (Huang, 1975a). Recently a new iododeoxyuridine (IUDR)-induced intracellular DNA polymerase in an Epstein-Barr virus (EBV)-producing hybrid cell line has also been reported (Miller et al., 1977). We present evidence that there are two different DNA polymerase activities associated with EBV, one intracellular and the other virion-associated. Both of these enzymes have certain biochemical characteristics which distinguish them from each other, and from the host-cell DNA polymerases found in lymphocytes.

Cell Line↗
PubMed1976

Sialic acid uptake by fibroblasts.

The existence of surface sialytransferases that use cytidine monophosphate (CMP)-sialic acid as substrate has been postulated in previous studies. This is based on the assumption that if whole, viable cells can catalyze the transfer of sialic acid from CMP-sialic acid to endogenous acceptors, then the transferases carrying out the reaction must be on the cell surface, provided that (1) CMP-sialic acid does not enter the cells, and (2) CMP-sialic acid does not break down outside the cells, yielding free sialic acid which then may enter the cells, in amounts large enough to explain the incorporation. We now report evidence showing that after incubation of intact NIL, BHK, and 3T3 fibroblasts with CMP-sialic acid, at least 78% of the sialic acid incorporated by these cells is the result of free sialic acid uptake. When cells growing in a monolayer were incubated with a mixture of CMP-[14C]sialic acid and [3H]CMP-sialic acid with a ratio of 3H/14C=0.60, this ratio was found to be markedly increased in whole cells. Chemical analyses of the radioactive species in the incubation medium showed that a considerable portion of the radiolabeled sugar nucleotide had broken down to cytidine, phosphoric acid, and sialic acid. Upon incubation of cells with doubly labeled sugar nucleotide in the presence of a large excess of both nonradiolabeled cytidine and sialic acid, the cells incorporated less than 6% of both isotopes. Incubation of cells with a mixture of CMP-[14C]sialic acid and [3H]sialic acid resulted in only 20-40% of the radioactivity within the cells being membrane bound, and 70-90% of this incorporation could be inhibited by the addition of 10 mM azide to the incubation medium. The possibility that a small fraction of the total incorporation of sialic acid by these cells is due to surface sialytransferases cannot be completely ruled out. The uptake of free sialic acid by these fibroblasts is concentration dependent and a portion of it is incorporated into glycoproteins and glycolipids. Considerable loss of cell integrity was observed when fibroblasts grown on plates were removed by (ethylenedinitrilo)-tetraacetic acid or trypsin and subsequently incubated in buffer, indicating that these preparations are not suitable for intact cell studies.

Azides↗
PubMed1976

Isolation and description of a menaquinone mutant from Bacillus licheniformis.

A menaquinone mutant (SG1) of Bacillus licheniformis has been isolated by selecting for colonies that are resistant to low levels of kanamycin (1.5 mug/ml) but sensitive to the same concentration of kanamycin in the presence of shikimate (25 mug/ml). The wild type (IU1) contained 0.38 +/- 0.02 nmol of menaquinone-7 (MK-7) per mg (dry weight) of cells when grown +/- shikimate, whereas SG1 had less than 0.01 nmol of MK-7 per mg (dry weight) of cells when grown in the presence of shikimate. SG1 had a generation time of 85 min, as compared to 24 min for IU1 grown +/- shikimate. SG1 doubled with a generation time of 28 min when grown in the presence of shikimate. IU1 consumed O2 at various rates depending on the stage of growth. A triphasic O2 consumption curve with maxima at mid-exponential phase, the transition from exponential to stationary phase, and early stationary phase was found for IU1 +/- shikimate and SG1 + shikimate. SG1 grown without shikimate consumed O2 at a low level (10 to 20% of IU1). Normal respiration could be restored to SG1 8.5 min after shikimate addition, whereas normal growth was not restored until 40 min after shikimate addition. Electron microscopic studies of SG1 and IU1 have indicated a morphological alteration in the mutant. SG1 is a dwarf cell as compared to IU1, when grown without shikimate. However, SG1 grown with shikimate became morphologically indistinguishable from IU1.

Bacillus↗
PubMedDate not supplied

Absence of brain spectrin(240/235) in dendrites of mammalian brain.

Spectrin is a major cytoskeletal component of the brain. At least 3 distinct spectrin subtypes are found in mammalian brain: brain spectrin(240/235) which is confined mainly to axons, brain spectrin(240/235E) which is localized largely in neural cell bodies and dendrites, and brain spectrin(240/235A) which is associated only with astrocytes. Recently, Ivy et al. reported that brain spectrin (240/235) was located in dendrites when tissues were fixed with 4% paraformaldehyde. To evaluate this matter further, rat cerebellar cortex prepared with and without aldehydes was stained with antibodies to brain spectrin(240/235) and examined using peroxidase (4-chloro-1-naphthol or avidin-biotin) or rhodamine to visualize the primary antibody. The preparations (10 microns and 40 microns sections) showed that brain spectrin(240/235) resided largely in axons with occasional staining of neuronal soma (Purkinje cells), but was not observed in dendrites. These results confirm earlier reports [e.g., (10,12)] showing the discrete compartmentalization of brain spectrin(240/235) in axons and cell bodies.

Animals↗
PubMedDate not supplied

Brain spectrin(240/235A): a novel astrocyte specific spectrin isoform.

We have previously demonstrated the existence of two distinct isoforms of spectrin in mammalian brain (23). Brain spectrin(240/235) is found primarily in neuronal axons and presynaptic terminals, and brain spectrin(240/235E) is located in neuronal cell bodies, dendrites and postsynaptic terminals, and oligodendrocytes. These isoforms are thought to play important roles in controlling the early events of synaptic transmission, axonal transport of organelles and vesicles, and lateral mobility of integral membrane proteins. In this study, we have utilized a panel of monoclonal antibodies to identify a novel astrocyte specific isoform(240/235A) with subunits of 240 kDa and 235 kDa in a 1:1 ratio. Double label indirect immunofluorescence has indicated that brain spectrin (240/235A) is distinct from brain spectrin (240/235E). This novel isoform located in the soma and processes of astrocytes may play a role in actin-membrane attachment, cellular architecture, strengthening of the membrane fabric, and translocation of cytoplasmic organelles and vesicles.

Animals↗