第17章细胞的社会联系
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Chapter 17
Cells in their social context 细胞的社会联系
Section 1 Cell Junctions
Major types of cell junctions in animal cells Cell-cell/matrix junctions have important roles in physical attachment and signal transduction
TK+ wild cell
Coculture in T medium (T is labeled with 32P)
Radioactive particles in cells formed gap junctions
TTP* entered from wild cell to mutant cell Why?
Communication junctions 通讯连接
Molecular Biology of the Cell, Fifth Edition (© Garland Science 2008)
Molecular Biology of the Cell, Fifth Edition (© Garland Science 2008)
2.2 Hemidesmosome (半桥粒)
Cell-Matrix adhesion junction
2.3 Adhesion belt (黏着带)
• Contractile bundle of actin filaments lies adjacent to the adhesion belt, and provides the motile force for the folding of epithelial cell sheets into tubes, vesicles
·Block the lateral movement of membrane
proteins, maintain cell polarity
2. Anchoring junctions
增强组织中细胞承受机械力的能力
Molecular Biology of the Cell, Fifth Edition (© Garland Science 2008)
1. Tight junction
图 17-1 小肠上皮细胞紧密连接结构
Roles of tight junctions:
• Permeability barrier 血脑屏障(BBB)
(From the World of the Cell, 2000)
• Epithelia cells can alter tight junctions transiently to selectively permit the flow of solutes and water---paracellular transport (ions, oligosa, aa)
2.1 Desmosome (桥粒): Give epithelia mechanical strength
Βιβλιοθήκη Baidu
• 形成整体网络，支持和抵抗外界压力与张力 自我免疫缺陷病——天泡疮（pemphigus）
(Karp. 2010)
Antibodies bind to and disrupt the desmosomes, resulting in a severe blistering of the skin, with leakage of body fluids into the loosened epithelium
Regulated by G protein and cAMP pathway, or different claudin molecules
Defects in the claudin 16 gene prevent the normal paracellular flow of Mg2+ in the kidney, resulting in an low blood level of Mg2+, leading to convulsions Regulate cell proliferation
(2)有一位学者研究发现，将放射性标记的蛋白质( 分子量比间隙连接允许通过的分子量大得多)显微 注射到野生型细胞中，结果在与之形成间隙连接的 突变细胞中出现了放射自显影信号。该学者认为这 一结果具有划时代的意义。因此，该学者得出了间 隙连接也能通过蛋白质等生物大分子的结论。但这 一结论是错误的。那么，请你解释为何突变细胞内 有放射自显影信号？(5分)
3.1 Gap Junctions
Diffusion<1KD
Electrical and chemical communication
• How to approve the role of gap junction in metabolic coupling
Thymine TK- Mutant cell kinase (TK)
Molecular Biology of the Cell, Fifth Edition (© Garland Science 2008)
2.4 Focal Adhesion (黏着斑)
维持细胞张力 细胞生长信号传递
3. Communication junctions
Animal Tissue Plant Tissue Gap junction Plasmodesma
TK+ TK-
Gap junction
Metabolic Coupling
相邻细胞形成间隙连接（gap junction）后可以实现代谢偶 联。若将胸苷激酶突变(TK-)的细胞和野生型细胞共培养在含有32P 标记的胸苷的培养基中，放射自显影实验发现TK-突变细胞核中没 有放射自显影颗粒信号，而野生型细胞核中有放射自显影信号。 但当TK-突变细胞与野生型细胞形成间隙连接后，这两种细胞核中 都有放射自显影信号。
(1)与正常细胞形成间隙连接的TK-突变细胞核中出现放射自显影 信号，有人认为很可能是野生型细胞中的TK通过间隙连接进入突 变细胞，导致突变细胞也能利用32P标记的胸苷进行DNA合成，也 有人认为是其它的原因，比如野生型细胞中合成的带有放射性标 记的DNA通过间隙连接进入突变细胞。请你分析其真正的原因是什 么。(5分)
Cells in their social context 细胞的社会联系
Section 1 Cell Junctions
Major types of cell junctions in animal cells Cell-cell/matrix junctions have important roles in physical attachment and signal transduction
TK+ wild cell
Coculture in T medium (T is labeled with 32P)
Radioactive particles in cells formed gap junctions
TTP* entered from wild cell to mutant cell Why?
Communication junctions 通讯连接
Molecular Biology of the Cell, Fifth Edition (© Garland Science 2008)
Molecular Biology of the Cell, Fifth Edition (© Garland Science 2008)
2.2 Hemidesmosome (半桥粒)
Cell-Matrix adhesion junction
2.3 Adhesion belt (黏着带)
• Contractile bundle of actin filaments lies adjacent to the adhesion belt, and provides the motile force for the folding of epithelial cell sheets into tubes, vesicles
·Block the lateral movement of membrane
proteins, maintain cell polarity
2. Anchoring junctions
增强组织中细胞承受机械力的能力
Molecular Biology of the Cell, Fifth Edition (© Garland Science 2008)
1. Tight junction
图 17-1 小肠上皮细胞紧密连接结构
Roles of tight junctions:
• Permeability barrier 血脑屏障(BBB)
(From the World of the Cell, 2000)
• Epithelia cells can alter tight junctions transiently to selectively permit the flow of solutes and water---paracellular transport (ions, oligosa, aa)
2.1 Desmosome (桥粒): Give epithelia mechanical strength
Βιβλιοθήκη Baidu
• 形成整体网络，支持和抵抗外界压力与张力 自我免疫缺陷病——天泡疮（pemphigus）
(Karp. 2010)
Antibodies bind to and disrupt the desmosomes, resulting in a severe blistering of the skin, with leakage of body fluids into the loosened epithelium
Regulated by G protein and cAMP pathway, or different claudin molecules
Defects in the claudin 16 gene prevent the normal paracellular flow of Mg2+ in the kidney, resulting in an low blood level of Mg2+, leading to convulsions Regulate cell proliferation
(2)有一位学者研究发现，将放射性标记的蛋白质( 分子量比间隙连接允许通过的分子量大得多)显微 注射到野生型细胞中，结果在与之形成间隙连接的 突变细胞中出现了放射自显影信号。该学者认为这 一结果具有划时代的意义。因此，该学者得出了间 隙连接也能通过蛋白质等生物大分子的结论。但这 一结论是错误的。那么，请你解释为何突变细胞内 有放射自显影信号？(5分)
3.1 Gap Junctions
Diffusion<1KD
Electrical and chemical communication
• How to approve the role of gap junction in metabolic coupling
Thymine TK- Mutant cell kinase (TK)
Molecular Biology of the Cell, Fifth Edition (© Garland Science 2008)
2.4 Focal Adhesion (黏着斑)
维持细胞张力 细胞生长信号传递
3. Communication junctions
Animal Tissue Plant Tissue Gap junction Plasmodesma
TK+ TK-
Gap junction
Metabolic Coupling
相邻细胞形成间隙连接（gap junction）后可以实现代谢偶 联。若将胸苷激酶突变(TK-)的细胞和野生型细胞共培养在含有32P 标记的胸苷的培养基中，放射自显影实验发现TK-突变细胞核中没 有放射自显影颗粒信号，而野生型细胞核中有放射自显影信号。 但当TK-突变细胞与野生型细胞形成间隙连接后，这两种细胞核中 都有放射自显影信号。
(1)与正常细胞形成间隙连接的TK-突变细胞核中出现放射自显影 信号，有人认为很可能是野生型细胞中的TK通过间隙连接进入突 变细胞，导致突变细胞也能利用32P标记的胸苷进行DNA合成，也 有人认为是其它的原因，比如野生型细胞中合成的带有放射性标 记的DNA通过间隙连接进入突变细胞。请你分析其真正的原因是什 么。(5分)