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G Sawicki

Publications and source records attributed to G Sawicki.

11 recordsLinked to original sources
PubMed1994

Expression of beta 1 integrin mRNAs in human leukemic blasts.

Adhesion receptors from the very late activation (VLA) (beta 1) integrin subfamily play a role in the cooperation of hematopoietic progenitors with bone marrow stroma, and the disregulated expression of these molecules, as evaluated by immunophenotyping, has been implicated in the acquisition of the malignant phenotype by hematopoietic cells. In the present study, Northern hybridization was used to determine the pattern of expression of transcripts for VLA subunits in: (i) leukemic blasts obtained from the peripheral blood of ten patients with acute myelogenous leukemia (AML) of different FAB subclasses; (ii) the human leukemic cell lines KG-1, HL-60, K-562, HEL and U-937; and (iii) normal hematopoietic cells. Most of the AML blasts and the cultured leukemic cells expressed mRNAs for the beta 1 and alpha 5 subunits (the only exception among the cell lines was KG-1 cells) and these transcripts were also found in normal bone marrow progenitors, peripheral blood mononuclear cells (PBMNC), and peripheral blood monocytes. While the alpha 4 transcript was detected in all cultured cells but K-562, and in normal circulating monocytes, it occurred in blasts from only two AML patients and was weakly expressed in mature PBMNC. No specific pattern of expression of beta 1, alpha 5, and alpha 4 transcripts could be related to cell differentiation or maturation in the AML blasts and leukemic cell lines tested. None of the primary AML blasts or cultured cells showed mRNA messages for alpha 2, alpha 3 or alpha 6 chains of the beta 1 integrins. The results suggest that, in some cases of AML, the malignant phenotype of leukemic blasts may be associated with down-regulated transcription of the alpha 4 integrin subunit.

Adult↗
PubMed1992

Sequence, structure, and expression of a wasp venom protein with a negatively charged signal peptide and a novel repeating internal structure.

An expression cDNA library prepared from mRNA from the venom gland of a parasitic wasp, Chelonus sp. near curvimaculatus, was screened with polyclonal antibodies against a 33-kDa venom protein from this wasp. Immunoreactive clones were sequenced, yielding a complete inferred sequence for a protein with an NH2 terminus identical with that of the 33-kDa protein. The structure of the cDNA showed an apparent encoded signal peptide, which was unusual in possessing 2 glutamic acid residues juxtapositioned next to, or replacing, the conventional basic residues. The bulk of the mature protein sequence which follows the NH2-terminal, 5000-kDa hydrophobic domain is composed of a dozen tandem repeats of a highly charged, approximately 14-residue sequence, except for the truncated eighth repeat which terminates in the only proline in this large domain. The primary structure is not closely related to any sequence in the GenBank data bank. Secondary structure analysis identified a turn occurring at or near each of 12 invariantly conserved serine residues. Further, the codon used for this serine was invariant, whereas other serines in the protein (including a nearly invariant serine 2 residues away) used various codons. Results of epitope mapping experiments supported a proposed tertiary structure in which the NH2-terminal 5-kDa forms a hydrophobic core, overlain with the charged repeats. Northern analysis of poly(A) RNA from the venom gland of young adult female wasps showed expression of a single 1-kilobase transcript, for which there is no corresponding message in normal or parasitized host larvae. The remarkable structure of this protein and structural data on other wasp venom proteins suggest an evolutionary pattern in which some proteins critical for venom function evolve by internal tandem duplication, and which are secreted after biosynthesis by a different mechanism from that used for proteins with classical signal peptides containing basic residues.

Amino Acid Sequence↗
PubMed1989

Cathepsin H from human placenta.

Cathepsin H was isolated from human placenta by autolysis, acetone fractionation, and chromatography on DEAE-cellulose, Sephadex G-75, hydroxyapatite and concanavalin A-Sepharose. The enzyme gave on SDS-polyacrylamide gel electrophoresis two bands of Mr 25,500 and 28,500. Two active forms of the enzyme, with pI of 6.0 and 6.45, were obtained by isoelectric focusing. The enzyme is stable over the pH range 5-7.5, whereas it becomes inactive on heating to 50 degrees C. Cathepsin H of human placenta, like the enzyme from other sources, hydrolyses protein and naphthylamide substrates, showing within the latter group the strongest preference towards arginine-beta-naphthylamide (pH optimum 6.8). The enzyme is inhibited by the known inhibitors of cysteine proteases and by placental cystatins.

Cathepsin H↗
PubMed1989

Cystatins of human placenta.

Two low-molecular protein fractions inhibiting cysteine proteases were isolated from human placenta by alkalization to pH 11, acetone fractionation, affinity chromatography on CM-papain-Sepharose 4B, and Sephadex G-75 gel filtration. The results of polyacrylamide gel electrophoresis, isoelectric focusing indicate that one of there fractions in a dimer of cystatins B, and another is a mixture of cystatins A and B.

Cathepsin H↗
PubMed1987

[Cystatins].

Explore the source record for details and available documents.

Amino Acid Sequence↗
PubMed1982

Insulin and beta receptor modulation of K homeostasis in nephrectomized dogs with hyperkalemia.

In nephrectomized dogs infused with 2 mEq KCl/kg/hr a homeostatic mechanism retards the development of hyperkalemia by transferring about 70% of the K load to intracellular fluid. beta Adrenergic receptor activity is importantly involved in the transfer process; halting it with propranolol reduces the proportion transferred to less than 35%. The addition of pancreatectomy increases the involvement of beta receptor activity; propranolol treatment now reduces the proportion transferred to less than 20%. Insulin treatment, on the other hand, not only improves transfer of a K load, it also alters the response to propranolol. Nephrectomized dogs treated with 2 U insulin/kg/hr deposit some 80% of the infused K in intracellular fluid. After beta receptor blockade, nearly 90% is transferred. The results suggest that in the K homeostatic mechanism of nephrectomized dogs, insulin and beta receptors may be reciprocally related. K transfer mediated by beta receptors improves after pancreatectomy, and insulin mediated K transfer improves after beta receptors are inactivated.

Aldosterone↗
PubMedDate not supplied

Cysteine proteinase inhibitors in human placenta.

When human placental extract was chromatographed on a Sephadex G-75 column, cysteine proteinase inhibitors with molecular weights of 80 000 and 12 300 were eluted. The high molecular weight peak (CPI-H) was identified as alpha-cysteine proteinase inhibitor. The thermostable low molecular weight peak (CPI-L) inhibited plant proteinases (papain, ficin and bromelain) as well as cathepsins B, H and L isolated from the human placenta. No cross-reactivity was observed between placental CPI-L and serum alpha-CPI.

Antibodies↗