注意

proteoglycan 蛋白聚糖
主要是糖,95%重量

glycoproteins 糖蛋白
主要是蛋白

ECM is made and oriented by the cells within it
eg.Fibroblasts成纤维细胞

glycosaminoglycans (GAGs)

amino sugar氨基糖 与 uronic acid糖醛酸 重复

highly negatively charged

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4种GAGs

hyaluronan
chondroitin sulfate
heparan sulfate
keratan sulfate

特性

  1. GAGs tend to adopt highly extended conformations that occupy a huge volume relative to their mass 善于填充整个空间
  2. GAGs form hydrated gels even at very low concentrations.由于带负电所以可以吸引正点离子然后通过渗透压吸水,高度含水
  3. GAGs enable the matrix to withstand compressive forces 用于承受压缩力

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Proteoglycan 蛋白聚糖

大部分GAGs与core protein结合形成proteoglycan

core protein在endoplasmic reticulum内质网形成
Polysaccharide chains are assembled on this core protein in the Golgi apparatus

proteoglycan 95%的重量来自碳水化合物

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一堆蛋白聚糖可以形成更大的aggrecan蛋白多聚糖👇
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fibrous proteins 纤维蛋白

strengthen and help organize the matrix, and give matrix resilience弹性

collagen 胶原蛋白

The major proteins of the ECM, constituting 25% of the total protein mass

triplet Gly-X-Y sequences,Gly是glycine甘氨酸,X Y也是氨基酸

long, stiff, triple-stranded helical三螺旋 structure 叫α链, α链还会与其他α链贴在一起形成superhelix👇
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elastin 弹性蛋白

highly hydrophobic

gives tissues the resilience to recoil after transient stretch

Adopt a loose “random coil” conformation
不受力时采用随机线圈构型

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a large class of noncollagen glycoproteins 非胶原糖蛋白

The extracellular matrix contains a large and varied type of glycoproteins that have multiple domains, each with specific binding sites for other matrix macromolecules大分子 and for receptors on the surface of cells.
有多种结合域👇
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Functions

  1. Contribute to both organizing the matrix and helping cells attach to it
  2. Guide cell movements in developing tissues
  3. Bind and influence the function of peptide肽 growth factors and other small molecules

Fibronectin(FN) 纤维粘蛋白

A large glycoprotein found in all vertebrates脊椎动物 and important for many cell- matrix interactions.

a dimer composed of two very large subunits joined by disulfide bonds at their C terminal ends 👇
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上面举着胶原纤维,下面连着intergin整联蛋白 👇
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Laminin (LN) 层粘连蛋白

The primary organizer of basal lamina基底膜

有三个亚基👇
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Basal lamina (basement membrane) 基底层

A specialized type of extracellular matrix

Functions

  • separates cells from underlying or surrounding connective tissue
  • forms the mechanical connection lies between two cell sheets
  • functions as a selective filter.
  • important in tissue regeneration after injur

Basal lamina can be organized in three ways👇
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The major components of the basal lamina are laminin and Type IV collagen👇
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