Proteinase activated receptor 2: role of extracellular loop 2 for ligand-mediated activation
Proteinase activated receptor 2: role of extracellular loop 2 for ligand-mediated activation
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DOI：
10.1038/sj.bjp.0702834
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发表时间：
1999-11-01
影响因子：
7.3
通讯作者：
Hollenberg, MD
中科院分区：
文献类型：
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作者：
Al-Ani, B;Saifeddine, M;Hollenberg, MD
1大鼠蛋白水解酶激活受体-2(PAR(2))突变体在大鼠KNRK细胞中稳定表达：(A)野生型(Wt)-PAR(2)；(B)PAR(2)PrR，其胞外环2(EL-2)序列P231E232E233-突变为PrR；(C)PAR(2)net，其EL-2序列，Peev变为NETL。细胞系对胰酶的敏感性(钙信号)进行了评估，在野生型PAR(2)中，受体激活肽SLIGRL-NH2、SLIGEL-NH2、反式肉桂酰基(TC)-LIGRLO-NH2和SFLLR-NH2.2 SLIGEL-NH2显示低效价(相对于SLIGRL-NH2为1：200)。3在PAR(2)PRR中，SLIGRL-NH2、TC-LIGRLO-NH2和SFLLR-NH2的活性降低了80-100倍。4在EL-2与蛋白酶激活受体-1(PAR(1))高度同源的PAR(2)网络中，PAR(1)衍生的多肽SFLLR-NH2的效力比wt-PAR降低100倍，而PAR(2)衍生的AP SLIGRL-NH2的效力降低10倍。相反，胰酶在PAR(2)中的效力与在wt-PAR(2)中几乎相同。5我们得出结论，PAR(2)中的酸性EL-2三肽pee在调节激动剂活性中起重要作用。NETL突变提示：(A)SLIGRL-NH2和SFLLR-NH2以一种不同的方式与PAR(2)相互作用，(B)SFLLR-NH2与PAR(2)的相互作用可能不同于与PAR(1)的相互作用。7与PAR(2)PRR和PAR(2)中的胰酶相比，SLIGRL-NH2的效力降低不同。
1 Rat proteinase-activated receptor-2 (PAR(2)) variants were stably expressed in rat KNRK cells: (a) wild-type (wt)-PAR(2); (b) PAR(2)PRR, with the extracellular loop 2 (EL-2) sequence P231E232E233-mutated to PRR and (c) PAR(2)NET, with the EL-2 sequence, PEEV changed to NETL. Cell lines were evaluated for their sensitivity (calcium signalling) towards trypsin and the receptor-activating peptides, SLIGRL-NH2, SLIGEL-NH2, trans-cinnamoyl(tc)-LIGRLO-NH2, and SFLLR-NH2.2 SLIGEL-NH2 exhibited low potency (1 : 200 relative to SLIGRL-NH2) in wild-type PAR(2). Its activity was increased 5 fold in PAR(2)PRR, but it was inactive in PAR(2)NET.3 In PAR(2)PRR, the potencies of SLIGRL-NH2, tc-LIGRLO-NH2, and SFLLR-NH2 were decreased by 80-100 fold. But, the potency of trypsin was decreased by only 7 fold.4 In PAR(2)NET highly homologous in EL-2 with proteinase-activated receptor-1 (PAR(1)), the potency of the PAR(1)-derived peptide, SFLLR-NH2, was reduced by 100 fold compared with wt-PAR, whereas the potency of the PAR(2)-derived AP, SLIGRL-NH2 was reduced 10 fold. In contrast, the potency of trypsin in PAR(2)NET was almost the same as in wt-PAR(2).5 We conclude that the acidic EL-2 tripeptide, PEE, in PAR(2) plays an important role in governing agonist activity.6 The data obtained with the PEEV-->NETL mutation suggested: (a) that SLIGRL-NH2 and SFLLR-NH2 interact in a distinct manner with PAR(2) and (b) that SFLLR-NH2 may interact differently with PAR(2) than it does with PAR(1).7 The differential reductions in the potencies of SLIGRL-NH2, compared with trypsin in the PAR(2)PRR and PAR(2)NET cell lines point to differences between the interactions of the trypsin-revealed tethered ligand and the free receptor-activating peptide with PAR(2).