Functional Analysis of LKB1/STK11 Mutants and Two Aberrant Isoforms Found in Peutz-Jeghers Syndrome Patients
Functional Analysis of LKB1/STK11 Mutants and Two Aberrant Isoforms Found in Peutz-Jeghers Syndrome Patients
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DOI：
10.1002/humu.9112
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发表时间：
2003-02-01
期刊：
影响因子：
3.9
通讯作者：
Resta, N.
中科院分区：
文献类型：
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作者：
Boudeau, J.;Kieloch, A.;Resta, N.
Peutz-Jeghers综合征（PJS）被认为是由广泛表达的丝氨酸/苏氨酸蛋白激酶LKB 1/STK 11突变引起的。最近的工作导致在一组PJS意大利患者中鉴定出四种突变体（R304 W，I177 N，K175-D176 del，L263 fsX 286）和两种新的异常LKB 1/STK 11 cDNA亚型（r291- 464 del，r485- 1283 del）。四个突变中的三个仅改变LKB 1/STK 11催化结构域中的1或2个氨基酸。在这里，我们证明，所有六个LKB 1/STK 11变异体分析是完全无活性的体外，因为他们不能在Thr 336，主要的LKB 1/STK 11自磷酸化位点，磷酸化的p53肿瘤抑制蛋白。我们还表明，6个变体中的5个完全定位于细胞核中，而野生型LKB 1/STK 11在细胞核和细胞质中均被检测到。最后，我们证明了所有6种LKB 1/STK 11变体，与野生型LKB 1/STK 11相比，不能抑制黑色素瘤G361细胞的生长。总之，这些结果表明，在本研究中研究的LKB 1突变导致丝氨酸/苏氨酸激酶活性的丧失，因此可能是PJS发展的主要原因，他们被分离的患者。(C)2003 Wiley-Liss，Inc.
Peutz-Jeghers Syndrome (PJS) is thought to be caused by mutations occurring in the widely expressed serine/threonine protein kinase named LKB1/STK11. Recent work has led to the identification of four mutants (R304W, I177N, K175-D176del, L263fsX286) and two novel aberrant LKB1/STK11 cDNA isoforms (r291-464del, r485-1283del) in a group of PJS Italian patients. Three of the four mutations only change 1 or 2 amino acids in the LKB1/STK11 catalytic domain. Here we demonstrate that all six LKB1/STK11variants analysed are completely inactive in vitro as they were unable to autophosphorylate at Thr336, the major LKB1/STK11 autophosphorylation site, and to phosphorylate the p53 tumour suppressor protein. We also show that 5 out of the 6 variants are entirely localised in the nucleus in contrast to the wild type LKB1/STK11, which is detected in both the nucleus and cytoplasm. Finally we demonstrate that all 6 LKB1/STK11 variants, in contrast to wild type LKB1/STK11, are unable to suppress the growth of melanoma G361 cells. Taken together, these results demonstrate that the LKB1 mutations investigated in this study lead to the loss of serine/threonine kinase activity and are therefore likely to be the primary cause of PJS development in the patients that they were isolated from. (C) 2003 Wiley-Liss, Inc.