Functional interactions between the proline-rich and repeat regions of tau enhance microtubule binding and assembly
Functional interactions between the proline-rich and repeat regions of tau enhance microtubule binding and assembly
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DOI：
10.1091/mbc.8.2.353
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发表时间：
1997-02-01
影响因子：
3.3
通讯作者：
Feinstein, SC
中科院分区：
文献类型：
--
作者：
Goode, BL;Denis, PE;Feinstein, SC
Tau是一种神经元微管相关蛋白，可促进微管在轴突中的组装、稳定性和捆绑。tau蛋白的两个不同区域对tau-微管相互作用很重要，一个是羧基端相对较好表征的“重复区域”（包含三个或四个不完善的18个氨基酸重复序列，由13或14个氨基酸长重复序列隔开），另一个是位于中心位置，相对较差表征的富含脯氨酸的区域。通过对tau的氨基末端截断分析，我们将富含脯氨酸的区域的微管结合活性定位为Lys(215)- asn(246)，并在该区域内鉴定了一个小序列（215）KKVAVVR(221)，该序列对三重复和四重复tau亚型的微管结合和组装都有很强的影响。定点诱变实验表明，这些能力主要来源于Lys(215)/Lys（216）和Arg（221）。与重复区对应的合成肽明显相反，单独对应Lys(215)-Asn（236）和Lys(215)-Thr（222）的肽很少或根本没有促进微管组装的能力，并且肽Lys(215)-Thr（222）不能有效抑制体外微管动力学。然而，将富含脯氨酸的区域序列(Lys（215)-Asn(246)）与其相邻的重复区域序列(Lys（215)- Lys(272)）结合在一个肽内，微管组装能力提高了10倍，表明富含脯氨酸的区域和重复区域之间存在分子内相互作用。通过富含脯氨酸和重复区域的序列氨基末端缺失也表明了tau蛋白区域的结构复杂性，这揭示了一种不寻常的功能丧失和获得模式。因此，这些数据导致了一个模型，在这个模型中，tau的有效微管结合和组装活动需要其重复序列和富含脯氨酸的区域之间的分子内相互作用。该模型调用了tau蛋白微管结合构象的结构复杂性，与之前的tau蛋白结构和功能模型有着根本的不同，这些模型将tau蛋白视为独立作用的微管蛋白结合位点的简单线性阵列。
Tau is a neuronal microtubule-associated protein that promotes microtubule assembly, stability, and bundling in axons. Two distinct regions of tau are important for the tau-microtubule interaction, a relatively well-characterized ''repeat region'' in the carboxyl terminus (containing either three or four imperfect 18-amino acid repeats separated by 13- or 14-amino acid long inter-repeats) and a more centrally located, relatively poorly characterized proline-rich region. By using amino-terminal truncation analyses of tau, we have localized the microtubule binding activity of the proline-rich region to Lys(215)-Asn(246) and identified a small sequence within this region, (215)KKVAVVR(221), that exerts a strong influence on microtubule binding and assembly in both three- and four-repeat tau isoforms. Site-directed mutagenesis experiments indicate that these capabilities are derived largely from Lys(215)/Lys(216) and Arg(221). In marked contrast to synthetic peptides corresponding to the repeat region, peptides corresponding to Lys(215)-Asn(236) and Lys(215)-Thr(222) alone possess little or no ability to promote microtubule assembly, and the peptide Lys(215)-Thr(222) does not effectively suppress in vitro microtubule dynamics. However, combining the proline-rich region sequences (Lys(215)-Asn(246)) with their adjacent repeat region sequences within a single peptide (Lys(215) Lys(272)) enhances microtubule assembly by 10-fold, suggesting intramolecular interactions between the proline-rich and repeat regions. Structural complexity in this region of tau also is suggested by sequential amino-terminal deletions through the proline-rich and repeat regions, which reveal an unusual pattern of loss and gain of function. Thus, these data lead to a model in which efficient microtubule binding and assembly activities by tau require intramolecular interactions between its repeat and proline-rich regions. This model, invoking structural complexity for the microtubule-bound conformation of tau, is fundamentally different from previous models of tau structure and function, which viewed tau as a simple linear array of independently acting tubulin-binding sites.