MUTATIONAL ANALYSIS OF THE YEAST A-FACTOR TRANSPORTER STE6, A MEMBER OF THE ATP BINDING CASSETTE (ABC) PROTEIN SUPERFAMILY
MUTATIONAL ANALYSIS OF THE YEAST A-FACTOR TRANSPORTER STE6, A MEMBER OF THE ATP BINDING CASSETTE (ABC) PROTEIN SUPERFAMILY
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DOI：
10.1002/j.1460-2075.1991.tb04947.x
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发表时间：
1991-12-01
期刊：
影响因子：
11.4
通讯作者：
MICHAELIS, S
中科院分区：
文献类型：
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作者：
BERKOWER, C;MICHAELIS, S
STE 6是酵母α-因子转运蛋白，是ATP结合盒蛋白超家族的成员，该超家族还包括哺乳动物多药耐药蛋白和囊性纤维化基因产物。这些蛋白质含有两个同源的一半，每个都有六个跨膜片段和一个预测的ATP核苷酸结合域。为了评估STE 6的两个半部分的重要性，并检查ATP结合盒超家族成员之间保守的残基的功能意义，我们将突变引入STE 6的核苷酸结合结构域。我们的分析表明，STE 6的两个半部分对功能至关重要，并且一些但不是所有的突变类似于已知导致囊性纤维化的突变，会损害STE 6的活性。为了进一步研究STE 6蛋白的每一半的功能贡献，我们切断了STE 6编码序列，并将转运蛋白的两半表达为单独的多肽。尽管“半分子”不能单独提供转运功能，但在同一细胞中两种半分子的共表达导致STE 6介导的α-因子转运的功能重建。
STE6, the yeast a-factor transporter, is a member of the ATP binding cassette protein superfamily, which also includes the mammalian multidrug resistance protein and the cystic fibrosis gene product. These proteins contain two homologous halves, each with six membrane spanning segments and a predicted ATP nucleotide binding domain. To assess the importance of the two halves of STE6, and to examine the functional significance of residues conserved among members of the ATP binding cassette superfamily, we introduced mutations into the nucleotide binding domains of STE6. Our analysis demonstrates that both halves of STE6 are critical for function and that some, but not all, mutations analogous to those known to result in cystic fibrosis impair STE6 activity. To examine further the functional contribution of each half of the STE6 protein, we severed the STE6 coding sequence and expressed the two halves of the transporter as separate polypeptides. Whereas 'half-molecules' are unable to provide transport function individually, co-expression of both half-molecules in the same cell leads to functional reconstitution of STE6-mediated a-factor transport.