490 likes | 1.24k Views
chapter 19. Cell Junctions and extra cellular matrix II. Desmosomes and hemidesmosomes both link to intermediate filaments. Cadherins also bind intermediate filaments together. Integrins link extracellular matrix to cytoskeleton.
E N D
chapter 19 Cell Junctions and extra cellular matrix II
Desmosomes and hemidesmosomes both link to intermediate filaments
Size of gap junction channel can be determined with fluorescent molecules of different sizes
A Gap junction connexon is made up of 6 transmembrane connexin subunits
The permeability of gap junctions can be regulated dopamine treatment reduces permeability of gap junctions to a fluorescent dye
In plant cells plasmodesmata perform many of the same functions as gap junctions
Structure of Cadherin – responsible for cell to cell adhesion in vertebrate cells
Ca2+ is required to establish cell to cell connection through cadherin
Three mechanisms that mediate cell-cell adhesion cadherins least common
Catenins join cadherins to actin filaments in adherence junctions
Summary of junctional and non-junctional adhesive mechanisms
Connective tissue underlying the epithelium contains a variety of cells and extracellular matrix components
Glycosaminoglycan (GAG) chains occupy large amounts of space and form hydrated gels
Hyaluronan, a simple GAG, occupies a large amount of space, thereby providing mechanical support
Collagen fibrils in tadpole skin This arrangement is also found in bone and the cornea
Each elastin protein in the network can expand and contract as a coil
Fibronectin is an extracellular protein that helps cells attach to the matrix
Connective tissue underlying the epithelium contains a variety of cells and extracellular matrix components