Search PubMed⌕ Search

Biomedical subjects

L A Goldsmith

Publications and source records attributed to L A Goldsmith.

At least 19 recordsLinked to original sources
PubMed1992

Organization and evolution of the human epidermal keratinocyte transglutaminase I gene.

Transglutaminases (TGases; protein-glutamine:amine gamma-glutamyltransferase, EC 2.3.2.13) are calcium-dependent crosslinking enzymes that modify proteins posttranslationally. Several distinct types of TGases have been identified, which appear to be encoded by a family of closely related genes. We isolated the gene encoding human keratinocyte-specific type I TGase (TGase I) and characterized its chromosomal organization. The TGase I gene consists of 15 exons separated by 14 introns and exhibits a restriction fragment length polymorphism. Exons appear to encode functional and/or structural domains: exon I and part of exon XV encode untranslated regions, whereas exons VII and XI contain the active site and a presumptive calcium-binding domain, respectively. Interestingly, exon VI of TGase I contains a consensus Arg-Gly-Asp tripeptide sequence whose presence suggests an intriguing extracellular function for the enzyme. We present a likely phylogenetic tree for seven known members of the TGase family based on amino acid sequence similarity. Arguments presented suggest that the active enzyme evolved first and the structural human erythrocyte membrane protein 4.2 (band 4.2) has undergone a rapid change in amino acid sequence. It follows that band 4.2 evolved from the type II TGases, whereas factor XIII subunit a evolved from the type I group.

Amino Acid Sequence↗
PubMed1992

Linkage of the epidermolytic hyperkeratosis phenotype and the region of the type II keratin gene cluster on chromosome 12.

Bullous congenital ichthyosiform erythroderma (epidermolytic hyperkeratosis) is a severe, generalized, lifelong disease of the skin. As in epidermolysis bullosa simplex, intraepidermal blisters and clumping of keratin intermediate filaments are characteristic. We report here linkage of the inheritance of this disease to the region of chromosome 12q containing the genes encoding type II keratins. This suggests that keratin gene mutations may underlie this complex hyperproliferative and hyperkeratotic phenotype.

Chromosome Mapping↗
PubMed1992

Transcriptional control of epidermal growth factor receptor by retinoic acid.

Retinoic acid (RA) and epidermal growth factor (EGF) regulate growth and differentiation of epithelial cells. RA has both direct and indirect effects on gene expression. Direct effects result from modulation of the transcriptional activity of genes, which contain RA response elements (RARE) recognized by trans-acting nuclear RA receptors (RARs). A second indirect mechanism for the modulatory effects of RA is by the induction or repression of growth factors and growth factor receptors. There is evidence for functional interactions between RA and the EGF receptor (EGFR). RA enhances the proliferative response of cultured keratinocytes to EGF, increases the number of EGFRs on the surface of some cells, and induces EGFR promoter activity in most cells. In contrast, immunoprecipitation, Northern blot, and nuclear run-on analysis described in this paper show that RA suppresses EGFR synthesis at the transcriptional level in human epidermoid carcinoma ME180 cells. Deletion analysis of EGFR gene promoter mutants linked to the chloramphenicol acetyltransferase gene revealed the existence of a region of the promoter, -771 to -384, which is responsive to RA. Gel retardation data indicated that a cell-type nuclear protein which binds to this novel element is suppressed by RA in a dose-dependent manner. This decrease coincides with a decreased steady-state level of RAR-gamma mRNA. These data strongly suggest that the EGFR promoter is regulated by RAR-gamma, which itself is under the control of RA. Other cell-specific trans-acting factors may be involved in this regulation.

Carcinoma, Squamous Cell↗
PubMed1991

Isolation of cDNA for human epidermal type I transglutaminase.

Keratinocytes of stratified epithelia, including the epidermis, express two distinct forms of transglutaminase, type I and type II. Type I transglutaminase activity is responsible for cell envelope formation in terminally differentiating cultured keratinocytes. Transglutaminase enzymatic activity has been associated with several proteins that are differentially expressed in vivo and in vitro. To elucidate the relationship between the epidermally expressed transglutaminases, cDNA for type I transglutaminase was cloned from a human high-calcium keratinocyte lambda gt11 library. cDNA fragments, generated by PCR primed with a mixture of oligonucleotides coding for five invariant amino acids in the active site, were used as a screening probe. Based on the sequence analysis of 1653 nt contained in the lambda 1-126a clone and on the pattern of expression of a complementary approximately 3-kb transcript, we report cloning of the epidermal type I transglutaminase gene. The expression of this gene is regulated by calcium ions and retinoic acid in cultured human keratinocytes. There are highly conserved regions near the active site cysteine residues that may be important for the enzyme's specialized functions.

Amino Acid Sequence↗
PubMed1991

Inhibition of human epidermal transglutaminases in vitro and in vivo by tyrosinamidomethyl dihydrohaloisoxazoles.

Tyrosinamidomethyl dihydrohaloisoxazoles (THX) irreversibly inhibit isolated epidermal transglutaminases and ionophore-induced cell envelope formation in malignant human keratinocytes. In cultured human foreskin keratinocytes cultured in 10(-5) M THX for 5 days, soluble and particulate transglutaminases were inhibited by 90% and 44-51%, respectively. Spontaneous cell envelope formation was inhibited up to 54%. When THX-treated keratinocytes were simultaneously incubated with 10(-5) M retinoic acid (RA), there was enhanced inhibition of cell envelope formation compared to either agent alone. The inhibitors were equally effective in keratinocytes incubated with fetal calf serum or delipidized serum. After THX was applied to normal human thoracic skin in vivo for 9 d, the soluble and particulate transglutaminases isolated from suction blister epidermis were inhibited 30% and 40%, respectively. THX may be effective in inhibiting both soluble and particulate transglutaminase activity in disorders with increased transglutaminase activity.

Cells, Cultured↗
PubMed1991

Epidermal type I transglutaminase (TGM1) is assigned to human chromosome 14.

Human epidermal type I transglutaminase coexists in keratinocytes with another cross-linking enzyme, tissue type II transglutaminase. There are at least five different forms of the enzyme in mammals. Gene mapping studies allowed us to determine whether the different transglutaminases are products of the same gene or separate genes. The gene encoding factor XIII subunit a transglutaminase (F13A1) was previously assigned to human chromosome 6, p24----p25. We demonstrate using somatic cell hybrids that the human epidermal type I transglutaminase gene (gene symbol is designated TGM1) is located on human chromosome 14, providing evidence that at least two human transglutaminases are encoded by separate genes.

Animals↗
PubMed1991

Characterization of keratocalmin, a calmodulin-binding protein from human epidermis.

Using affinity-purified calmodulin-binding proteins from human epidermis we have developed a monoclonal IgM antibody, ROC 129.1, to a human desmosomal calcmodulin-binding protein. This antibody reacts with a submembranous 250-kD protein from human keratinocytes and stains human epidermis in a "cell-surface pattern". Permeability studies indicated that the epitope with which this monoclonal reacts is on the inner surface of the cell membrane. Immunoelectronmicroscopy localized the antigen to the desmosome. The epitope is restricted to stratified squamous epithelia and arises between 8-12 wk of fetal development. This desmosomal calmodulin-binding protein, which we have termed keratocalmin, may be involved in the calcium-regulated assembly of desmosomes.

Animals↗
PubMed1991

Impetigo herpetiformis associated with hypocalcemia of congenital rickets.

A 30-year-old woman with congenital rickets and autosomal recessive ichthyosis developed impetigo herpetiformis in the second trimester of her first pregnancy. This condition was temporally related to her discontinuation of vitamin D supplements and subsequent hypocalcemia. No associated systemic symptoms were observed, and a healthy baby was delivered prematurely at 34 weeks' gestation. This report supports the association between hypocalcemia and impetigo herpetiformis and raises theoretical questions regarding a relationship between vitamin D metabolism and various epidermal hyperproliferative states.

Adult↗
PubMed1991

Intraepithelial anchoring fibril components.

Cultured human keratinocytes and cultured human cervical carcinoma cells (ME-180) contained intracellular pools of antigens that reacted with the anchoring fibril antibodies AF1 and AF2. In keratinocytes, these antigens formed a basement membrane-like structure near the apical portions of the cells. Using flow cytometric techniques, pretreatment of the ME-180 cells with acetone revealed large intracellular pools of antigen. The intracellular epitope was calcium sensitive. Some forms of recessive dystrophic epidermolysis bullosa have retention of intracellular portions of the anchoring fibril suggesting a relation of the intracellular anchoring fibril antigens to that disease.

Acetone↗
PubMed1990

Modulation of epidermal growth factor receptors by retinoic acid in ME180 cells.

Retinoic acid (RA) increases epidermal growth factor (EGF) receptors in many cells; in ME180 cells, a human epidermoid carcinoma, RA resulted in a dose- and time-dependent reduction of EGF binding. In RA-treated ME180 cells, binding was 41% of the control. The reduction of EGF binding was due to a decrease in the number of receptors, from 8.7 x 10(4) to 3.6 x 10(4) per cell. The difference was present 8 h after the addition of RA and was reversible 3 days after its removal. Scatchard analysis indicated that RA did not change the binding affinity of EGF (Kd = 1 nM). Also, RA did not alter the rate of EGF internalization or the down-regulation induced by exogenous EGF. Flow-cytometric analysis revealed that RA did not alter the cell cycle. Soluble cell membrane extracts were prepared in a Tris buffer with protease inhibitors, immunoprecipitated, electrophoresed, and immunoblotted with an antiserum to EGF receptors. The EGF receptor band of Mr 170,000 was decreased in RA-treated cells. These results suggest that RA reduces the synthesis of EGF receptors in ME180 cells.

Carcinoma, Squamous Cell↗
PubMed1990

Monoclonal antibodies to two different epitopes in a 30-kD CNBr peptide of the K1 and K2 keratins.

Two anti-keratin monoclonal antibodies, Kab-2 and Kab-3, with specificities for different epitopes of type II (basic) human epidermal keratins, were produced. These antibodies had different immunofluorescent staining patterns on human fetal epidermis. Western blots and solid phase RIA showed both antibodies bound to 65-67-kD basic keratins (K1 and K2) extracted from foreskin epidermis. Competitive binding studies with the two Kab antibodies and other anti-keratin monoclonal antibodies showed that Kab-2 and Kab-3 recognized related epitopes, distinct from the epitopes recognized by other anti-keratin antibodies AE-1, 2, and 3. Kab-2 and Kab-3 epitopes were distinguished by differences in their reactivity with peptides generated by Staphylococcus aureus V8 protease digestion of the K1 keratin; the antibodies recognized both common and unique peptides. Western blots of cyanogen bromide digests of the K1 keratin showed that both Kab antibodies reacted with a 30-kD fragment of the molecule presumed to be the N-terminal CNBr peptide. We interpret these data to indicate that in tissues, portions of the N-terminal region of the K1 keratin are differentially available for reaction with these monoclonal antibodies and that morphologic differences in staining with monoclonal antibodies to the same molecule can reflect epitope specificity or epitope availability related to supramolecular organization.

Animals↗