Chapter 20. E-Cadherin Isoforms and Function
Introduction
Analyze the Data 20-1: E-Cadherin Isoforms and Function
Researchers have isolated two mutant E-cadherin isoforms that are hypothesized to function differently from wild-type E-cadherin. An E-cadherin-negative mammary carcinoma cell line was transfected with the mutant E-cadherin genes A (part a in the figure; triangles), or B (part b; triangles) or the wild-type E-cadherin gene (filled circles) and compared with nontransfected cells (open circles) in an aggregation assay. In this assay, cells were first dissociated by trypsin treatment and then allowed to aggregate in solution over a period of minutes. To demonstrate that the observed adhesion was mediated by cadherin, the cells were pretreated with a nonspecific antibody (left panels) or a function-blocking anti-E-cadherin monoclonal antibody (right panels).
Question
SyfRluJaMq+QcgnBbD9u4F/XUSMtr3XUIor7eVuLuW4tNVwMyZN7lA58DOW2Lg5XT6ky5ROVVFyU8lrvTf0H/7crCH9f2HlUmVZxp57l7XS0sQJz0iklmpTiUieSL7VOhAm4cnq+2zwM6CTh2eUT1qB8HLe3wG/y5ZSohCl3z8C2g6AOsF81QLTSLPF7Q/d1d1W4A+90PB7ldqfBpVvNZX3KWy0=Cells transfected with wild-type E-cadherin aggregate more than untransfected cells because the increase in E-cadherin allows for more cell-cell interactions via the ECM.
Question
kqf9LOqIZEKHumRIUYasM6MUWQ/G005yDLo+JUOv/2xKCUFdwdWVsIByXEmSitwnihMUMB4xiaL3p0s2vU6An1drPdcr5sJhYHlCicWwlN0L7i1RNi+Ja1GJXc1zHn9H1z/PUgz2zTnh5ZLB7AaVfd8qYd0=Mutant A behaves almost identically to the wild-type E-cadherin in the aggregation assay; therefore, this mutation does not change the function of E-cadherin as far as hemophilic interactions are concerned. Expression of mutant B, however, does not result in increased aggregation, so this particular mutation does alter the adhesive qualities of E-cadherin.
Question
V4lvFpykPPHmXp45KWXMrZPM/D1h7ZSit8BMCjQWWjW3bMqWNL2dPNasbge5BzNDTktdtCMBK0XgBghW1SMHE9Tv0nZZQ62iag0Zg1y19Bzc04NNFgKzSyon+unko8cXPd8fk7F6En6BlSJ+dmyGljl3WnpxVhUwbnaTY/WxNSJ8cp750Bj/VWPlB5jXg8Zd9kSIaNH/Y1XoWskSIficTQ==The monoclonal antibody specific for E-cadherin blocks the resulting aggregation because it binds to E-cadherin and blocks homophilic inter-actions. In contrast, the nonspecific antibody does not specifically interact with E-cadherin, and does not block homophilic interactions.
Question
iUT+KGDsbi70IipYUQoxCtcP881WZ0TBIO2Uwx/uNh4FJHXcZH7YgVXaKBuuLPOxGAWTED7rd1oTI7HlqrYKjHensAR7lyx2Vj8hImFH3drDu8FsN9vZcZ41JXfA7D13UsPFuL1v1E289xfQvolSb4kwqDNgeeapnVIeqtGPE+ba/F7E3BolwLuWExsAKwfQYYsZ8WYB1ORl6Ep1LN5pIsnj0N2WRsBW609jMYXGKj4P3Y0DMX8i3EJVUjBEShfaaeoZ2ceYZ+nSvMDKjuxcDA==Since cadherins require calcium for function, lowering the calcium in the media during the assay would lower the aggregation ability.
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