| Question |
Answer |
| Numerous different linking proteins tie the membranes of adjacent epithelial cells closely together around their apical perimeters. What are these called? |
tight junctions |
| tight junctions are also called what? |
zoneal occludens |
| what are bound by 2 adaptor proteins and cadherins? |
belt desmosome |
| multiple belt desmosomes anchor what? |
circumferential belt |
| Constriction of these microfilaments around the “necks” of these cells pull them into a bottleneck shape: |
circumferential belt |
| transmembrane complexes allowing diffusion of small molecules between cells are what? |
gap junctions |
| isolated “spot welds” joining two cells at their lateral surfaces; serve to tie together the cytoskeletons of multiple cells across a tissue. what are these structures? |
spot desmosomes |
| Complexes that anchor epithelial cells to the extracellular matrix of the basal lamina are what? |
hemidesmosomes |
| structures that anchor microfilament stress fibers to the basal surface of fibroblasts and cancer cells which have attached to the substratum are what structures? |
focal adhesions |
| what is a heterodimeric, transmembrane protein that binds a number of factors on both sides of the membrane? |
integrin |
| these junctions seal epithelial layers against diffusion by preventing molecules from passing between the cells: |
tight junctions |
| tight junctions also block passage of what? |
components of the plasma membrane (lipids, proteins) between the apical and basal regions of epithelial cells |
| gap junctions have how many polypeptides per junction? what shape are they? |
12; hexagonal |
| what are some examples of molecules that pass through gap junctions? |
calcium for muscles, ions for nerves, camp for many tissues |
| belt desmosomes are also called what? |
adherens junctions |
| these link the microfilament cytoskeleton of one cell with that of another cell: |
belt desmosomes |
| which desmosome is most like a focal adhesion? |
belt desmosome |
| belt desmosomes anchor what fibers to the membrane? |
microfilaments |
| in belt desmosomes, the filaments are linked to the same adaptor proteins used in what other junction? |
focal adhesions |
| what are a family of calcium dependant transmembrane glycoproteins, often required for tissue specific cell-cell binding during development? |
cadherins |
| belt desmosomes are linked by what? |
cadherins |
| what are microfilament bundles attached to belt desmosomes, which encircle the apical perimeter of epithelial cells just below the tight junctions? |
circumferential belt |
| what is an autoimmune disorder that attacks one of the transmembrane linker proteins in spot desmosomes? |
pemphigus vulgaris |
| in hemidesmosomes, on the cytoplasmic side, intermediate filaments are bound to a pair of plaques consisting of what? |
adaptor proteins |
| adaptor proteins in hemidesmosomes are held to the plasma membrane by integrin, which is tied to what? |
laminin in the basal lamina |
| integrin is also used in focal adhesions where it links what to what? |
microfilaments to fibronectin |
| in focal adhesions, on the outer side of the membrane, integrin binds what to link the cytoskeleton with the extracellular matrix? |
fibronectin |
BIOL3326 Forms
