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a. __: when lymphocytes removed from body and injected back would return ot sites where they originally were
lymphocyte homing
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b. __comprise a family of integral membrane glycoproteins that recognize and bind to a particular arrangement of __that project from the surfaces of other cells i. the name of this class of __ is derived from “__,” a general term for a compound that binds ot specific __groups
- Selectins
- sugars in the oligosaccharides
- cell-surface receptors
- lectin
- carbohydrate
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a. __ possess a small __, a __, and a large __ segment that consists of a number of separate modules, including an outermost domain that acts as the __
i. three known selectins: __
- Selectins
- cytoplasmic domain
- single membrane-spanning domain
- extracellular
- lectin
- E-selectin (endothelial cells); P-selectin (platelets and endothelial cells); L-selectin (leukocytes)
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1. all three selectins recognize a particular grouping of __at the ends of the __ of certain complex __
a. binding of selectins to their carbohydrate ligands requires __
- sugars
- carbohydrate cahains
- glycoproteins
- calcium
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a. as a group, selectins mediate __between circulating leukocytes and vessel walls at sites of __
b. selectins are well-suited for __ because the bond that they form with their __ become stronger when the __
- transient interactions
- inflammation and clotting
- capturing fast moving particles
- ligands
- interaction is under mechanical stress
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a. antibodies, a type of protein called __, were found to consist of polypeptide chains composed of a number of similar domains
i. each of these __ is composed of __ organized into a tightly folded structure
- Ig
- Ig domains
- 70-110 amino acids
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a. as a group, these proteins are members of the __
i. most members are involved in different __functions, but some of these proteins mediate __
1. originally evolved as __ and only secondarily took on their functions as __ of the vertebrate immune system
immunoglobulin superfamily, or IgSF
immune
calcium-independent cell-cell adhesion
cell-adhesion mediators
effectors
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a. most IgSF cell-adhesion molecules mediate the specific interactions of __
i. still, some IgSF members, like __, mediate __between __ cells.
- lymphocytes with cells required for immune response
- VCAM, NCAM, and L1,
- adhesion
- nonimmune
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1. NCAM and LI play important roles in __, __, and other events during the development of the NS
a. like __and other proteins in cell adhesion, the IgSF cell-adhesion molecules have a __ and are composed of individual domains of similar structure to domains in other proteins
- nerve outgrowth, synapse formation
- fibronectin
- modular constructuion
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a. importance of L1 in neural development revealed in several ways
i. mutations—> __ (water in the brain), mental retardation, etc.
ii. __: missing two large nerve tracts
b. various types of proteins serve as __for IgSF cell-surface molecules
i. most integrins facilitate __of cells to their __, but a few integrins mediate __ by binding to proteins on other cells
- hydrocephalus
- L1-deficiency disease
- ligands
- adhesion
- substratum
- cell-cell adhesion
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What are cadherins?
a. large family of glycoproteins that mediate Ca2+- dependent cell-cell adhesion nd transmit signals from the ECM to the cytoplasm
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__ typically join cells of similar type to one another and do so by binding to the same __ present on the surface of the neigbhboring cell
cadherins x2
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1. this property was first demonstrated by genetically engineering cells that were normally nonadhesive to express one of a variety of different cadherins
a. cells then mixed in various combos and their interactions monitored
i. cells expressing one species of __ adhered to other cells expressing the same __
-
a. __ construction
b. types?
i. “__”; contain a relatively large extracellular segment consisting of __domains of similar size and structure, a signgle transmembrane segment,a dn a small __
- modular
- E-cadherin, N-cadherin (neural), and P-cadherin (placental)
- classical
- five tandem
- cytoplasmic domain
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1. the __ is often associated with members of the __family of cytosolic proteins, which have a dual role: __
- cytoplasmic domain
- catenin
- tether cadherins to the cytoskeleton and transmit signals to the cytoplasm and nucleus
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a. __from the same cell-surface associate laterally to form __
b. __ form bridges between successive domains of a given molecule, maintaining the extracellular portion of each __in a rigid conformation required for cell adhesion
i. adhesion between cells results from the interaction between the extracellular domains of cadherins from opposing cells to form a “cell-adhesion zipper”
- cadherins
- parallel dimers
- calcium ionscadherin
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a. different types of cells bearing different __likely engage in different types of __
the greater the number of interacting __ in a cluster, the greater the __ between apposing cells
- cadherins
- interactiosn
- cadherins
- strength of adhesion
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a. cadherin-mediated adhesion is responsible for the ability of __
b. they may be the single most important factor in moldng cells into __ in the embryo and holding them together in the adult
i. the loss of cadherin function à __
- like cells to “sort out” of mixed aggregates
- cohesive tissues
- malignant tumors
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a. __ is characterized by change, in gene expression, cell shape, motility, etc.
i. __mediate many changes in __that are required to construct the tissues and organs of an embryo, called __
1. ex: epithelial-mesenchymal transition: epithelial cells form into mesenchyme or vice versa, which will eventually give rise to mesodermal tissues like blood, muscle, and bone
- embryonic development
- cadherins
- adhesive contacts
- morphogenesis
-
a. cells of the __(the cohesive epithelial layer) at the dorsal surface of the early embryo display __ on their surface, which promote close association with one another
-
a. formation of NS is characterized by changes in __ where, following __, the dorsal surface is covered with a single-celled epithelial layerà __ tissues
i. at this point, they stop expressing__ and begin expressing __
- cadherin expression,
- gastrulation
- ectodermal
- E-Cadherin
- N-cadherin
-
a. whereas __are typically distributed diffusely all along the surfaces of two adherent cells, they also participate in the formation of specialized __
- cadherins
- intercellular junctions
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