Exam II Pt. 7

a.      __: when lymphocytes removed from body and injected back would return ot sites where they originally were

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

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: __

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 __

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 __

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

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

a.      most IgSF cell-adhesion molecules mediate the specific interactions of __
                                                              i.      still, some IgSF members, like __, mediate __between __ cells. 

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 

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 

What are cadherins?

__ 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

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 __

1.      the __ is often associated with members of the __family of cytosolic proteins, which have a dual role: __

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”

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     

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 __

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

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 __

a.      whereas __are typically distributed diffusely all along the surfaces of two adherent cells, they also participate in the formation of specialized __