HARE-Mediated Endocytosis of Hyaluronan and Heparin Is Targeted by Different Subsets of Three Endocytic Motifs.
HARE-Mediated Endocytosis of Hyaluronan and Heparin Is Targeted by Different Subsets of Three Endocytic Motifs.
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DOI：
10.1155/2015/524707
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发表时间：
2015-01-01
影响因子：
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通讯作者：
Weigel, Paul H
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文献类型：
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作者：
Pandey, Madhu S;Harris, Edward N;Weigel, Paul H
透明质酸(HA)内吞作用受体(HARE)是一种多功能的循环清除受体，可与14种不同的配体结合，包括HA和肝素(HEP)，它们与不同的非重叠位点结合。胞浆结构域(CD)靶向包被核介导摄取的四个功能内吞模体(M)：YSYFRI(2485)(M1)、FQHF(2495)(M2)、NPLY(2519)(M3)和DPF(2534)(M4)。我们之前发现(Pandey et al.J.Biol.化学。21453、2008年)，即M1、M2和M3介导HA的内吞作用。在这里，我们评估了具有单一基序缺失或仅包含单一基序的HARE变体内吞HA或HEP的能力。缺少M1、M3或M4(与HA摄取不同的子集)的单一基序缺失变体显示HEP内吞作用降低，尽管M3最活跃；剩余的冗余基序不能弥补其他基序的丢失。令人惊讶的是，仅含有M3的Hare CD变体内化了HA和Hep，而仅含有M2或M4的变体不内吞任何一种配体。Hare CD突变体对HA和HEP的内化是动态依赖的，并被高渗透压抑制，证实了胞苷介导的内吞作用。结果表明，靶向涂层凹坑摄取的多个CD基序之间存在复杂的关系，M3基序具有更基本的作用。
The hyaluronan (HA) receptor for endocytosis (HARE) is a multifunctional recycling clearance receptor for 14 different ligands, including HA and heparin (Hep), which bind to discrete nonoverlapping sites. Four different functional endocytic motifs (M) in the cytoplasmic domain (CD) target coated pit mediated uptake: (YSYFRI(2485) (M1), FQHF(2495) (M2), NPLY(2519) (M3), and DPF(2534) (M4)). We previously found (Pandey et al. J. Biol. Chem. 283, 21453, 2008) that M1, M2, and M3 mediate endocytosis of HA. Here we assessed the ability of HARE variants with a single-motif deletion or containing only a single motif to endocytose HA or Hep. Single-motif deletion variants lacking M1, M3, or M4 (a different subset than involved in HA uptake) showed decreased Hep endocytosis, although M3 was the most active; the remaining redundant motifs did not compensate for loss of other motifs. Surprisingly, a HARE CD variant with only M3 internalized both HA and Hep, whereas variants with either M2 or M4 alone did not endocytose either ligand. Internalization of HA and Hep by HARE CD mutants was dynamin-dependent and was inhibited by hyperosmolarity, confirming clathrin-mediated endocytosis. The results indicate a complicated relationship among multiple CD motifs that target coated pit uptake and a more fundamental role for motif M3.