Cell–Cell Junctions and Extracellular Matrix (2A) Practice Test

In an intestinal epithelial model, a cytokine exposure causes internalization of occludin and claudins from the apical junctional complex. TEER decreases, but the rate of endocytosis of a labeled nutrient transporter at the apical membrane is unchanged. Based on the vignette, which conclusion is most consistent with the affected cellular process?

Keratinocytes from a patient with skin blistering show normal tight junction protein localization but reduced desmoglein expression at cell borders. In a mechanical stretch assay, the monolayer tears at cell–cell boundaries despite normal cell viability. Based on the vignette, which conclusion is most consistent with the disrupted cellular interaction?