Structural and Functional Aspects of the Multiplicity of Neu Differentiation Factors
| Autor: | Duanzhi Wen, Sidney V. Suggs, Devarajan Karunagaran, Naili Liu, Rod L. Cupples, Yi Luo, Ann M. Janssen, Noa Ben-Baruch, David B. Trollinger, Victoria L. Jacobsen, Shi-Yuan Meng, Hsieng S. Lu, Sylvia Hu, David Chang, Weining Yang, Donna Yanigahara, Raymond A. Koski, Yosef Yarden |
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| Rok vydání: | 1994 |
| Předmět: |
Gene isoform
Signal peptide DNA Complementary Receptor ErbB-2 Neuregulin-1 Molecular Sequence Data Gene Expression Biology Transfection Proto-Oncogene Proteins Animals Humans Amino Acid Sequence RNA Messenger Cloning Molecular Neuregulin 1 Phosphotyrosine Molecular Biology Peptide sequence DNA Primers Glycoproteins Neuregulins Base Sequence Sequence Homology Amino Acid C-terminus Alternative splicing Cell Biology Recombinant Proteins Transmembrane protein Rats ErbB Receptors Molecular Weight Transmembrane domain Genes Biochemistry biology.protein Tyrosine Sequence Alignment Research Article |
| Zdroj: | Molecular and Cellular Biology. 14:1909-1919 |
| ISSN: | 1098-5549 |
| Popis: | We used molecular cloning and functional analyses to extend the family of Neu differentiation factors (NDFs) and to explore the biochemical activity of different NDF isoforms. Exhaustive cloning revealed the existence of six distinct fibroblastic pro-NDFs, whose basic transmembrane structure includes an immunoglobulin-like motif and an epidermal growth factor (EGF)-like domain. Structural variation is confined to three domains: the C-terminal portion of the EGF-like domain (isoforms alpha and beta), the adjacent juxtamembrane stretch (isoforms 1 to 4), and the variable-length cytoplasmic domain (isoforms a, b, and c). Only certain combinations of the variable domains exist, and they display partial tissue specificity in their expression: pro-NDF-alpha 2 is the predominant form in mesenchymal cells, whereas pro-NDF-beta 1 is the major neuronal isoform. Only the transmembrane isoforms were glycosylated and secreted as biologically active 44-kDa glycoproteins, implying that the transmembrane domain functions as an internal signal peptide. Extensive glycosylation precedes proteolytic cleavage of pro-NDF but has no effect on receptor binding. By contrast, the EGF-like domain fully retains receptor binding activity when expressed separately, but its beta-type C terminus displays higher affinity than alpha-type NDFs. Likewise, structural heterogeneity of the cytoplasmic tails may determine isoform-specific rate of pro-NDF processing. Taken together, these results suggest that different NDF isoforms are generated by alternative splicing and perform distinct tissue-specific functions. |
| Databáze: | OpenAIRE |
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