Evidence for phosphorylation and oligomeric assembly of presenilin 1
Evidence for phosphorylation and oligomeric assembly of presenilin 1
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DOI：
10.1073/pnas.94.10.5090
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发表时间：
1997-05-13
影响因子：
11.1
通讯作者：
Gandy, S
中科院分区：
文献类型：
--
作者：
Seeger, M;Nordstedt, C;Gandy, S
早老素1（PS1）中的致病性突变与大约50%的早发性家族性阿尔茨海默病相关，PS1被内切蛋白水解切割以产生30-kDa的N-末端片段（NTF）和18-kDa的C-末端片段（CTF）。使用用人PS1转染的COS 7细胞，我们发现佛波醇12，13-二丁酸酯和毛喉素增加人CTF的丝氨酸残基的磷酸化状态。人CTP的磷酸化导致电泳迁移率从18 kDa的单一主要种类转变为20-23 kDa的倍增物，这种迁移率变化也在转染到小鼠神经母细胞瘤（N2 a）细胞中的人PS 1中观察到。用噬菌体λ蛋白磷酸酶处理磷酸化的CTF双联体消除了20-至23-kDa的倍增体，同时增强了18-kDa的种类，与电泳迁移率变化是由于向18-kDa物质中加入磷酸盐的解释一致，NTF和CTF以超过100 kDa的估计质量从凝胶过滤柱洗脱，表明这些片段作为寡聚化物质存在。在PS1 CTF磷酸化后，含有NTF或CTF的寡聚体的表观质量不变。因此，在PS1 CTF的磷酸化/去磷酸化循环期间，可以维持PS1片段的结合。
Pathogenic mutations in presenilin 1 (PS1) are associated with approximate to 50% of early-onset familial Alzheimer disease, PS1 is endoproteolytically cleaved to yield a 30-kDa N-terminal fragment (NTF) and an 18-kDa C-terminal fragment (CTF), Using COS7 cells transfected with human PS1, we have found that phorbol 12,13-dibutyrate and forskolin increase the state of phosphorylation of serine residues of the human CTF, Phosphorylation of the human CTP resulted in a shift in electrophoretic mobility from a single major species of 18 kDa to a doubler of 20-23 kDa, This mobility shift was also observed with human PS1 that had been transfected into mouse neuroblastoma (N2a) cells, Treatment of the phosphorylated CTF doublet with phage lambda protein phosphatase eliminated the 20- to 23-kDa doubler while enhancing the 18-kDa species, consistent with the interpretation that the electrophoretic mobility shift was due to the addition of phosphate to the 18-kDa species, The NTF and CTF eluted from a gel filtration column at an estimated mass of over 100 kDa, suggesting that these fragments exist as an oligomerized species, Upon phosphorylation of the PS1 CTF, the apparent mass of the NTF- or CTF-containing oligomers was unchanged, Thus, the association of PS1 fragments may be maintained during cycles of phosphorylation/dephosphorylation of the PS1 CTF.