| 1. |
- Minet, Ariane D., et al.
(author)
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Teneurin-1, a vertebrate homologue of the Drosophila pair-rule gene ten-m, is a neuronal protein with a novel type of heparin-binding domain
- 1999
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In: Journal of Cell Science. - 0021-9533. ; 112:12, s. 2019-2032
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Journal article (peer-reviewed)abstract
- The Drosophila gene ten-m is the first pair-rule gene not encoding a transcription factor, but an extracellular protein. We have characterized a highly conserved chicken homologue that we call teneurin-1. The C-terminal part harbors 26 repetitive sequence motifs termed YD-repeats. The YD-repeats are most similar to the core of the rhs elements of Escherichia coli. Related repeats in toxin A of Clostridium difficile are known to bind specific carbohydrates. We show that recombinantly expressed proteins containing the YD-repeats of teneurin-1 bind to heparin. Furthermore, heparin lyase treatment of extracts of cells expressing recombinant YD-repeat protein releases this protein from high molecular mass aggregates. In situ hybridization and immunostaining reveals teneurin-1 expression in neurons of the developing visual system of chicken and Drosophila. This phylogenetic conservation of neuronal expression from flies to birds implies fundamental roles for teneurin-1 in neurogenesis. This is supported by the neurite outgrowth occurring on substrates made of recombinant YD-repeat proteins, which can be inhibited by heparin. Database searches resulted in the identification of ESTs encoding at least three further members of the teneurin family of proteins. Furthermore, the human teneurin-1 gene could be identified on chromosome Xq24/25, a region implied in an X-linked mental retardation syndrome.
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| 2. |
- Baumgartner, Stefan, et al.
(author)
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The discoidin domain family revisited : new members from prokaryotes and a homology-based fold prediction
- 1998
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In: Protein Science. - : Wiley. - 0961-8368 .- 1469-896X. ; 7:7, s. 31-1626
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Journal article (peer-reviewed)abstract
- Members of the discoidin (DS) domain family, which includes the C1 and C2 repeats of blood coagulation factors V and VIII, occur in a great variety of eukaryotic proteins, most of which have been implicated in cell-adhesion or developmental processes. So far, no three-dimensional structure of a known example of this extracellular module has been determined, limiting the usefulness of identifying a new sequence as member of this family. Here, we present results of a recent search of the protein sequence database for new DS domains using generalized profiles, a sensitive multiple alignment-based search technique. Several previously unrecognized DS domains could be identified by this method, including the first examples from prokaryotic species. More importantly, we present statistical, structural, and functional evidence that the D1 domain of galactose oxidase whose three-dimensional structure has been determined at 1.7 A resolution, is a distant member of this family. Taken together, these findings significantly expand the concept of the DS domain, by extending its taxonomic range and by implying a fold prediction for all its members. The proposed alignment with the galactose oxidase sequence makes it possible to construct homology-based three-dimensional models for the most interesting examples, as illustrated by an accompanying paper on the C1 and C2 domains of factor V.
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| 3. |
- Zeidman, Ruth, et al.
(author)
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Novel and classical protein kinase C isoforms have different functions in proliferation, survival and differentiation of neuroblastoma cells
- 1999
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In: International Journal of Cancer. - 0020-7136. ; 81:3, s. 494-501
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Journal article (peer-reviewed)abstract
- To elucidate the possibility of utilizing protein kinase C (PKC) isoforms as target genes in neuroblastoma therapy, 5 neuroblastoma cell lines and neuroblastoma tumor specimens were examined for PKC isoform expression pattern and the cell lines were analyzed for sensitivity to PKC inhibition. All cell lines [IMR-32, LAN-2, LAN-5, SH-SY5Y and SK-N-BE(2)] expressed alpha, betaII, delta and epsilon isoforms of PKC, while no PKCeta or theta protein was detected in any cell line. PKCgamma was found only in LAN-2 cells. PKCalpha, betaII and delta were detected in 5 neuroblastoma tumors and PKCepsilon in 4 out of 5 tumors. Exposure to the PKC inhibitors GF109203X, Go 6976 or Go 6983 caused a decrease whereas activation of PKC with 12-O-tetradecanoyl phorbol 13-acetate caused an increase in the number of neuroblastoma cells. The effect of Go 6976 was due to both inhibited proliferation and to increased apoptosis. While GF109203X suppressed neurite outgrowth induced by a growth factor combination, Go 6976 potentiated neurite outgrowth. Our data suggest a role for classical PKC isoforms in neuroblastoma growth and survival and for novel isoforms in neurite outgrowth.
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