Term
| What are the proteins that enable cells to adhere to each other and the ECM by binding to sequences in collagen, fibronectin, and laminin? |
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Definition
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Term
| What do cadherins do that is different from integrins? |
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Definition
| They are calcium dependent. They don't usually bind the ECM. |
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Term
| What do occludins and caudins do? |
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Definition
| They bind at tight junctions and prevent leakage at those sites. |
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Term
| What are connexons and what are they made of and where do they occur? |
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Definition
| Connexons are made of 6 connexin proteins. They form a tunnel between cells. This is called a gap junction. |
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Term
| Why might gap junctions be important? |
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Definition
| They are important in cardiac tissue for example, because the calcium can spread all around and you get contractions happening at the same time. |
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Term
| What protein do you think is common in the ecm of cardiac tissue? |
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Definition
| elastin because there's a lot of movement and you need resilient. Also in lungs for recoil. |
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Term
| How can an integrin be activated? |
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Definition
| Sometimes they can be activated by coming into contact with the ECM components (ie fibronectin). Also, binding to cytoskeletal proteins can causes activation by focal adhesion kinase. |
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Term
| Which type of protein attaches ECM to cytoskeleton? How does it do this and what else is involved? |
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Definition
| Well, the integrin binds the cytoskeleton (actin!) thanks to the focal adhesion kinase and an adaptor. They also bind fibronectin in the ECM. |
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Term
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Definition
| actin and myosin II. Actin polymerizes close to the cell membrane, which pushes the cell membrane forward. Attachment happens there with the ECM to hold it in the new position. Then, myosin II contracts at the tail to move it forward. The tail attachments are lost in this process and have to reanchor. |
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Term
| What is the actin area in the cell called? |
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Definition
| the actin cortex. its around the cell membrane |
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Term
| What is an adherens junction? What cell adhesion molecules are involved? |
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Definition
| It joins actin to actin. The cadherins are what join the actin to actin. There is usually an adaptor protein between actin and cadherin. |
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Term
| What is a desmosome? What proteins are used? |
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Definition
| This is intermediate filament to intermediate filament. They usually use cadherins as well. There is a linker protein between cadherin and intermediate filament. Bundles of keratin filaments criss-cross cytoplasm. |
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Term
| What is a gap junction? What proteins are used? |
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Definition
| Connexon is made of 6 connexins. Cell to cell pipe essentially. |
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Term
| What is a tight junction, what forms it? Where is it especially important? |
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Definition
| cadherins and occludins for these water tight seals. These are especially important in epithelial cells to prevent infection/fluid/etc from slipping beneath. |
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Term
| What is a hemidesmosome? What protein does it use to attach? |
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Definition
| Hemidesmosome goes from cell to ECM. It uses integrin, which then attaches to ECM adherin proteins like laminin. |
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Term
| Whats the deal with signal transduction and the ECM? |
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Definition
| Integrins can bind ligands in the ECM which cause kinases to activate stuff in the cell. |
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