Cell Junctions, Cell Adhesion, and the Extracellular Matrix：细胞连接,细胞粘附,细胞外基质
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• Pathway Guidance to Lead Cells Home: • Chemotaxis vs. Chemo-avoidance: • Ligands/Receptors/Second Messengers • N-CAMS and transmembrane adhesion molecules help mediate
Figure 19-13 Molecular Biology of the Cell (© Garland Science 2019)
Epithelial-mesenchymal transition
• In mesenchymal cells the adhesion molecules are switched off.
Cell Junctions, Cell Adhesion, and the Extracellular Matrix
Cell adhesion
The c-adherins
Why is cell-cell adhesion so important to understand?
• Migrating cells must reach, recognize, bind and stay with their target cells, tissues and organs!
The cells segregate according to the cadherins they express
Figure 19-12c Molecular Biology of the Cell (© Garland Science 2019)
Cadherin-dependent cell sorting
Table 19-2 Molecular Biology of the Cell (© Garland Science 2019)
Compaction of an early mouse embryo.
At the 8-cell stage they start expressing E-cadherins
Dimer anchored by tx-membrane sequences Localization of sub-types:
E-epithelial N-neuronal P-placental VE-endothelial For instance: N-cadherin binds to other N-cadherins, but not
to bind to other cells or know if they are in the correct location.
Lets review some of the options available. Know one item that
makes each unique.
N-CAMS: Ca+Independent
Cadherin expression during construction of the nervous system
E-cadherin
N-cadherin
Figure 19-12a,b Molecular Biology of the Cell (© Garland Science 2019)
• The transition is regulated by gene regulatory components named Slug, Snal and Twist. They affect E-cadherin expression
• Twist suppresses E-cadherin. It is involved in malignant transformation.
Four functional classes of cell junctions in animal tissues.
Figure 19-2 Molecular Biology of the Cell (© Garland Science 2019)
Table 19-1 Molecular Biology of the Cell (© Garland Science 2019)
to E, P or VE-cadherins This keeps neurons attached to other neurons! Important to vertebrates and invertebrate animals Classic extracellular Cadherin binds to actin on intracellular side. Non-Classic binds tonofilament on inside: for extra strength
Figure 19-10 Molecular Biology of the Cell (© Garland Science 2019)
Selective dispersal and reassembly in
an vertebrate embryo
Figure 19-11 Molecular Biology of the Cell (© Garland Science 2019)
A classical experiment: mesoderm cells (green), neural plate cells (blues) and epithelial cells (Red) were reaggregate random. They sort out as in a normal embryo
If potential neurons don’t lose N-cadherins, they can’t migrate! About 85% of cancers are epithelial in nature (due to high
replication rate), metastasis is linked to a loss of E-cadherins
Summary of the various types of cell junctions in animals
Figure 19-3 Molecular Biology of the Cell (© Garland Science 2019)
There are a variety of options available to cells when they seek
Figure 19-9b Molecular Biology of the Cell (© Garland Science 2019)
Many cadherin molecules are in a junction, functioning like a Velcro.
Figure 19-9c Molecular Biology of the Cell (© Garland Science 2019)
The transmembrane adhesion molecules link the cytoskeleton to extracellular structures
interactions Cadherins: cell-cell Integrins: cell-matrix
movie
Figure 19-4 Molecular Biology of the Cell (© Garland Science 2019)
Homophilic versus heterophilic binding of cadherins
Figure 19-8 Molecular Biology of the Cell (© Garland Science 2019)
Cadherin structure
Extracellular domains of a classical cadherin (C-cadherin)
The cadherin superfamily:
Figure 19-7 Molecular Biology of the Cell (© Garland Science 2019)
Table 19-3 Molecular Biology of the Cell (© Garland Science 2019)
Linkage of classical cadherin to actin filaments
Figure 19-14 Molecular Biology of the Cell (© Garland Science 2019)
Figurwk.baidu.com 19-9a Molecular Biology of the Cell (© Garland Science 2019)
Ca binds in the hinge regions between cadherin domains, and prevent the flexing. Without Ca the molecule is floppy and adhesion fails
Figure 19-5 Molecular Biology of the Cell (© Garland Science 2019)
Cadherins are a class of Ca++Dependent cell-cell adhesion molecules which are important in embryogenesis. Their loss permits cells to migrate within the chick embryo to become muscle.
• Important implications in embryogenesis, cancer, infection, transplantation potentials (stem cells) and disease!
• Tissue Development in the Embryo/Adult: • Epithelial cell to basal lamina: post burn skin • Neural crest cell in embryo: amputee nervous system • Endothelium and blood vessels: cancer
Cadherin diversity in the central nervous system
Mre than 70 other cadherins are expressed in CNS, they guide and maintain the organizatiof the brain
Figure 19-6 Molecular Biology of the Cell (© Garland Science 2019)
binding of cells to the ECM and each other!
Two main ways in which animal cells are bound together: •Connective tissue •Epithelial cells.
Figure 19-1 Molecular Biology of the Cell (© Garland Science 2019)
• Bind to other N-CAMS
Cadherins: Ca-Dependent
• Bind to other cadherins
Selectins: don’t bind each other. Specialized to bind target glycoproteins
Intergrins: bind laminin of the basal lamina or fibronectin in the ECM or to other cells.
Figure 19-13 Molecular Biology of the Cell (© Garland Science 2019)
Epithelial-mesenchymal transition
• In mesenchymal cells the adhesion molecules are switched off.
Cell Junctions, Cell Adhesion, and the Extracellular Matrix
Cell adhesion
The c-adherins
Why is cell-cell adhesion so important to understand?
• Migrating cells must reach, recognize, bind and stay with their target cells, tissues and organs!
The cells segregate according to the cadherins they express
Figure 19-12c Molecular Biology of the Cell (© Garland Science 2019)
Cadherin-dependent cell sorting
Table 19-2 Molecular Biology of the Cell (© Garland Science 2019)
Compaction of an early mouse embryo.
At the 8-cell stage they start expressing E-cadherins
Dimer anchored by tx-membrane sequences Localization of sub-types:
E-epithelial N-neuronal P-placental VE-endothelial For instance: N-cadherin binds to other N-cadherins, but not
to bind to other cells or know if they are in the correct location.
Lets review some of the options available. Know one item that
makes each unique.
N-CAMS: Ca+Independent
Cadherin expression during construction of the nervous system
E-cadherin
N-cadherin
Figure 19-12a,b Molecular Biology of the Cell (© Garland Science 2019)
• The transition is regulated by gene regulatory components named Slug, Snal and Twist. They affect E-cadherin expression
• Twist suppresses E-cadherin. It is involved in malignant transformation.
Four functional classes of cell junctions in animal tissues.
Figure 19-2 Molecular Biology of the Cell (© Garland Science 2019)
Table 19-1 Molecular Biology of the Cell (© Garland Science 2019)
to E, P or VE-cadherins This keeps neurons attached to other neurons! Important to vertebrates and invertebrate animals Classic extracellular Cadherin binds to actin on intracellular side. Non-Classic binds tonofilament on inside: for extra strength
Figure 19-10 Molecular Biology of the Cell (© Garland Science 2019)
Selective dispersal and reassembly in
an vertebrate embryo
Figure 19-11 Molecular Biology of the Cell (© Garland Science 2019)
A classical experiment: mesoderm cells (green), neural plate cells (blues) and epithelial cells (Red) were reaggregate random. They sort out as in a normal embryo
If potential neurons don’t lose N-cadherins, they can’t migrate! About 85% of cancers are epithelial in nature (due to high
replication rate), metastasis is linked to a loss of E-cadherins
Summary of the various types of cell junctions in animals
Figure 19-3 Molecular Biology of the Cell (© Garland Science 2019)
There are a variety of options available to cells when they seek
Figure 19-9b Molecular Biology of the Cell (© Garland Science 2019)
Many cadherin molecules are in a junction, functioning like a Velcro.
Figure 19-9c Molecular Biology of the Cell (© Garland Science 2019)
The transmembrane adhesion molecules link the cytoskeleton to extracellular structures
interactions Cadherins: cell-cell Integrins: cell-matrix
movie
Figure 19-4 Molecular Biology of the Cell (© Garland Science 2019)
Homophilic versus heterophilic binding of cadherins
Figure 19-8 Molecular Biology of the Cell (© Garland Science 2019)
Cadherin structure
Extracellular domains of a classical cadherin (C-cadherin)
The cadherin superfamily:
Figure 19-7 Molecular Biology of the Cell (© Garland Science 2019)
Table 19-3 Molecular Biology of the Cell (© Garland Science 2019)
Linkage of classical cadherin to actin filaments
Figure 19-14 Molecular Biology of the Cell (© Garland Science 2019)
Figurwk.baidu.com 19-9a Molecular Biology of the Cell (© Garland Science 2019)
Ca binds in the hinge regions between cadherin domains, and prevent the flexing. Without Ca the molecule is floppy and adhesion fails
Figure 19-5 Molecular Biology of the Cell (© Garland Science 2019)
Cadherins are a class of Ca++Dependent cell-cell adhesion molecules which are important in embryogenesis. Their loss permits cells to migrate within the chick embryo to become muscle.
• Important implications in embryogenesis, cancer, infection, transplantation potentials (stem cells) and disease!
• Tissue Development in the Embryo/Adult: • Epithelial cell to basal lamina: post burn skin • Neural crest cell in embryo: amputee nervous system • Endothelium and blood vessels: cancer
Cadherin diversity in the central nervous system
Mre than 70 other cadherins are expressed in CNS, they guide and maintain the organizatiof the brain
Figure 19-6 Molecular Biology of the Cell (© Garland Science 2019)
binding of cells to the ECM and each other!
Two main ways in which animal cells are bound together: •Connective tissue •Epithelial cells.
Figure 19-1 Molecular Biology of the Cell (© Garland Science 2019)
• Bind to other N-CAMS
Cadherins: Ca-Dependent
• Bind to other cadherins
Selectins: don’t bind each other. Specialized to bind target glycoproteins
Intergrins: bind laminin of the basal lamina or fibronectin in the ECM or to other cells.