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12 Cards in this Set
- Front
- Back
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1. What would happen to multicellular organisms without cell adhesion?
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Without adhesion, cells would not stick together, resulting in no organization
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2. List the four classes of cell junctions and the function of each.
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1. Anchoring Junctions: Attach cells to neighboring cells or ECM; tethered to cytoskeletal elements inside cell (actin or intermediate filaments)
2. Occluding Junctions: Tight junctions; Seal adjacent epithelial cells together, preventing passage of most dissolved molecules from one side of the epithelial sheet to the other 3. Channel-forming Junctions: Gap junction or communicating junction; Create passageways linking the cytoplasms of adjacent cells; regulated diffusion 4. Signal-relaying Junctions: allow signals to be relayed from cell to cell across their plasma membranes; neuronal signaling |
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3. If a cell wanted to adhere to the ECM using intermediate filaments what type of cell junction should it use?
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Anchoring junction using Hemidesmosomes
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3. If a cell wanted to adhere to the ECM using actin filament what type of cell junction should it use? |
Anchoring junction using Focal Adhesion
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4. What transmembrane protein family functions to adhere cells to the ECM?
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Integrins
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5. What type of cell junction is a desmosome? Does it adhere cells to other cells or to ECM? What cytoskeletal filaments are involved?
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Desmosomes are a type of Anchoring Junction
It adheres cells to other cells It used intermediate filaments |
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6. What type of cell junction is a hemidesmosome? Does it adhere cells to other cells or to ECM? What cytoskeletal filaments are involved?
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Hemidesmosomes are anchoring cell junctions used in anchoring junctions to connect epithelial cells and the underlying basal lamina
They adhere cells to ECM and involve intermediate filaments binding to anchoring proteins, which bind to integrins |
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7. How are desmosomes different from adherens junctions? How are they similar?
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Both are cell-cell anchoring junctions.
Desmosomes link intermediate filaments in one cell to those in another, where adherens junctions link actin filaments in one cell to those in anther Both intermediate filaments and actin filaments bind to anchoring proteins, which bind to transmembrane proteins called Cadherins |
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8. What are cadherins? What is the fundamental difference between cadherins and integrins?
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Cahderins are transmembrane proteins that mediate cell-cell adhesion that have an affinity for other cadherins
They require Ca2+ in order to bind Integrins mediate cell-ECM binding where Cadherins mediate cell-cell binding; integrins undergo conformational changes |
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9. What cell type are tight junctions commonly found in? What is their function? Why is this important? What are the critical transmembrane proteins involved?
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Found in the intestine to prevent bacteria from entering other tissues and in stomach to contain the acid to the stomach
TM proteins are claudins and occludins which create an impermeable seal |
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10. What are selectins? What cell type expresses these proteins? What cell type do they bind to? Why is this an important interaction?
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Belong to lectin family of cell-surface carbohydrate-binding proteins
They mediate transient, cell-cell adhesion in the bloodstream; endothelial cells of blood vessels express selectins They bind to white blood cells They bind to white blood cells as an immune response to sequester white blood cells (which sequester integrins once bound to selectins) to react to infection or inflammation |
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11. NCAM and ICAM are both cell adhesion molecules that belong to the ______________ protein superfamily. Do these molecules bind cells to other cells or to ECM? What is the difference between NCAM and ICAM?
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NCAM and ICAM belong to the Immunoglobin protein superfamily
They bind cell to other cells. NCAM is found on different cell types, where ICAM is found only on endothelial cells NCAM mediates hemophilic binding, where ICAM mediates heterophilic binding to integrins on white blood cells during immune response |
