Lactadherin (formerly BA46), a membrane-associated glycoprotein expressed in human milk and breast carcinomas, promotes Arg-Gly-Asp (RGD)-dependent cell adhesion.
Lactadherin (formerly BA46), a membrane-associated glycoprotein expressed in human milk and breast carcinomas, promotes Arg-Gly-Asp (RGD)-dependent cell adhesion.
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DOI：
10.1089/dna.1997.16.861
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发表时间：
1997-07
影响因子：
3.1
通讯作者：
M. R. Taylor;J. Couto;C. Scallan;R. Ceriani;J. Peterson
中科院分区：
文献类型：
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作者：
M. R. Taylor;J. Couto;C. Scallan;R. Ceriani;J. Peterson
乳胶粘附素是人类乳汁脂肪球膜的一种主要糖蛋白，在人类母乳中含量丰富，在人类乳腺癌中也有表达。以前，我们已经证明了成熟蛋白BA46有三个结构域：一个含有Arg-Gly-Asp(RGD)细胞黏附序列的表皮生长因子(EGF)样结构域，以及与凝血因子V和VIII中发现的类似的C1和C2结构域。乳粘附素与其牛(MGP57/53)和小鼠(MFG-E8)同源物的比对表明，RGD序列在进化过程中一直是保守的，这表明RGD序列并不是偶然的。我们证明，使用Triton X-114相分离纯化的乳粘附素可促进绿猴肾细胞(MA104)、小鼠成纤维细胞(3T3-L1)和乳腺癌细胞(ELL-G)对RGD依赖的细胞附着。乳胶粘附素特异的单抗MC3抑制与纯化的乳粘附素的结合，这表明纯化过程中的污染物不是结合的原因。此外，抗整合素α(V)β3的单抗LM609可抑制MA104细胞对乳胶粘附素的附着。这些结果表明乳黏附素通过整合素促进RGD依赖的细胞黏附。乳胶粘附素在加热和还原条件下的变性减少了细胞附着，这表明细胞对RGD的最佳附着取决于序列的结构呈现。
Lactadherin, a major glycoprotein of the human milk fat globule membrane, is abundant in human breast milk and expressed in human breast carcinomas. Previously, we have shown that the mature protein, formerly known as BA46, has three domains: an epidermal growth factor (EGF)-like domain containing an Arg-Gly-Asp (RGD) cell adhesion sequence and C1 and C2 domains similar to those found in coagulation factors V and VIII. An alignment of lactadherin with its bovine (MGP57/53) and murine (MFG-E8) homologs shows that the RGD sequence has been conserved during evolution, suggesting that the RGD sequence is not fortuitous. We demonstrate that lactadherin purified using Triton X-114 phase partitioning promotes RGD-dependent cell attachment of green monkey kidney cells (MA104), mouse fibroblast cells (3T3-L1), and breast carcinoma cells (ELL-G). A lactadherin-specific monoclonal antibody, Mc3, inhibits attachment to purified lactadherin, suggesting that contaminants in the purification are not responsible for binding. In addition, the anti-integrin alpha(v)beta3 monoclonal antibody LM609 inhibits cell attachment of MA104 cells to lactadherin. These results demonstrate that lactadherin promotes RGD-dependent cell adhesion via integrins. Denaturation of lactadherin with heat and reducing conditions diminished cell attachment, suggesting that optimal cell attachment to RGD is dependent on the structural presentation of the sequence.