Role of the alpha1 and alpha2 integrin cytoplasmic domains in cell morphology, motility and responsiveness to stimulation by the protein kinase C pathway
| Autor: | Samuel A. Santoro, Mary M. Zutter, Quiwei Gai, Zhengzhi Li, Haochuan Wang, Xun Yang, Bruce Linders |
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| Rok vydání: | 2000 |
| Předmět: |
Cytoplasm
Integrins DNA Complementary Receptors Collagen MAP Kinase Signaling System Protein subunit Recombinant Fusion Proteins Integrin Integrin alpha1 Integrin alpha2 Gene Expression Phosphatidylinositol 3-Kinases Antigens CD Cell Movement Complementary DNA Extracellular Cell Adhesion Humans Integrin-linked kinase Receptor Protein Kinase C Cell Size biology General Medicine Flow Cytometry Hematopoietic Stem Cells Cell biology Protein Structure Tertiary Transmembrane domain Biochemistry biology.protein Collagen K562 Cells |
| Zdroj: | Cell adhesion and communication. 7(4) |
| ISSN: | 1061-5385 |
| Popis: | The alpha1beta1 and alpha2beta1 integrins, extracellular matrix receptors for collagens and/or laminins, have similarities in structure and ligand binding. Recent studies suggest that the two receptors mediate distinct post-ligand binding events and are not simply redundant receptors. To discern the mechanisms by which the two receptors differ, we focused on the roles of the cytoplasmic domains of the alpha subunits. We expressed either full-length alpha1 integrin subunit cDNA (X1C1), full-length alpha2 integrin subunit cDNA (X2C2), chimeric cDNA composed of the extracellular and transmembrane domains of alpha2 subunit and the cytoplasmic domain of alpha1 (X2C1), chimeric cDNA composed of the extracellular and transmembrane domains of alpha1 subunit and the cytoplasmic domain of alpha2 (X1C2), alpha1 cDNA truncated after the GFFKR sequence (X1C0) or alpha2 cDNA truncated after the GFFKR sequence (X2C0) in K562 cells. Although the cytoplasmic domains of the alpha1 and alpha2 subunits were not required for adhesion, the extent of adhesion at low substrate density was enhanced by the presence of either the alpha1 or alpha2 cytoplasmic tail. Spreading was also influenced by the presence of an alpha subunit cytoplasmic tail. Activation of the protein kinase C pathway with phorbol dibutyrate-stimulated motility that was dependent upon the presence of the alpha2 cytoplasmic tail. Both the phosphatidylinosotide-3-OH kinase and the mitogen-activated protein kinase pathways were required for phorbol-activated, alpha2-cytoplasmic tail-dependent migration. |
| Databáze: | OpenAIRE |
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