Primary structure and cellular localization of chicken brain myosin-V (p190), an unconventional myosin with calmodulin light chains.
Primary structure and cellular localization of chicken brain myosin-V (p190), an unconventional myosin with calmodulin light chains.
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DOI：
10.1083/jcb.119.6.1541
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发表时间：
1992-12
影响因子：
7.8
通讯作者：
Mooseker, M S
中科院分区：
文献类型：
--
作者：
Espreafico, E M;Cheney, R E;Matteoli, M;Nascimento, A A;De Camilli, P V;Larson, R E;Mooseker, M S
最近对p190（一种从脊椎动物大脑中纯化的钙调蛋白（CM）结合蛋白）的生化研究表明，这种蛋白质作为与结合的CM的复合物纯化，与肌球蛋白具有许多共同性质（Espindola，F.美国，E. M. Espreafico，M. V. Coelho，A. R. Martins，F. R. C. Costa，M. S. Mooseker和R. E.拉森1992. 118：359-368）。为了确定p190是否是蛋白质的肌球蛋白家族的成员，分离并测序了一组编码鸡脑p190全长蛋白质序列的重叠cDNA。通过对鸡脑p190产生的溴化氰肽进行微序列分析，证实了推断的一级结构是p190的一级结构。推测的鸡脑p190蛋白的一级结构表明，这种1，830-氨基酸（aa）212，509-D）蛋白是一种新的非常规肌球蛋白结构类别的成员，该结构类别包括由小鼠稀释位点和酿酒酵母MYO 2基因编码的基因产物。我们命名的p190-CM复合物“肌球蛋白-V”的基础上的29个肌球蛋白重链（HC），这表明，这种肌球蛋白，头部结构的基础上，头域的详细序列比较的结果，是第五的六个不同的结构类别的肌球蛋白到目前为止被描述。与小鼠稀释和酵母MYO 2基因的假定产物一样，鸡肌球蛋白-V hc的头部结构域（aa 1-764）连接到“颈部”结构域（aa 765-909），该“颈部”结构域由大约23-aa“IQ基序的6个串联重复组成。“所有已知的肌球蛋白在它们的头-尾连接处都含有至少一个这样的基序;这些IQ基序可能作为钙调蛋白或轻链结合位点发挥作用。鸡肌球蛋白V的尾部结构域由最初的511个氨基酸组成，预计形成卷曲螺旋α螺旋的几个片段，随后是末端410个氨基酸的球状结构域（aa，1，421 - 1，830）。有趣的是，尾部结构域的一部分（aa，1，094 - 1，830）与来自小鼠脑的723-aa蛋白共享58%的氨基酸序列同一性，所述723-aa蛋白被报道为谷氨酸脱羧酶。鸡肌球蛋白-V的颈部区域，其中包含的IQ-基序，被证明含有CM的结合位点，通过分析CM结合到细菌表达的融合蛋白，包含头，颈，尾结构域。肌球蛋白-V在脑和培养细胞中的免疫定位显示，这种肌球蛋白在神经元和非神经元细胞中的分布不寻常。（400字处截断摘要）
Recent biochemical studies of p190, a calmodulin (CM)-binding protein purified from vertebrate brain, have demonstrated that this protein, purified as a complex with bound CM, shares a number of properties with myosins (Espindola, F. S., E. M. Espreafico, M. V. Coelho, A. R. Martins, F. R. C. Costa, M. S. Mooseker, and R. E. Larson. 1992. J. Cell Biol. 118:359-368). To determine whether or not p190 was a member of the myosin family of proteins, a set of overlapping cDNAs encoding the full-length protein sequence of chicken brain p190 was isolated and sequenced. Verification that the deduced primary structure was that of p190 was demonstrated through microsequence analysis of a cyanogen bromide peptide generated from chick brain p190. The deduced primary structure of chicken brain p190 revealed that this 1,830-amino acid (aa) 212,509-D) protein is a member of a novel structural class of unconventional myosins that includes the gene products encoded by the dilute locus of mouse and the MYO2 gene of Saccharomyces cerevisiae. We have named the p190-CM complex "myosin-V" based on the results of a detailed sequence comparison of the head domains of 29 myosin heavy chains (hc), which has revealed that this myosin, based on head structure, is the fifth of six distinct structural classes of myosin to be described thus far. Like the presumed products of the mouse dilute and yeast MYO2 genes, the head domain of chicken myosin-V hc (aa 1-764) is linked to a "neck" domain (aa 765-909) consisting of six tandem repeats of an approximately 23-aa "IQ-motif." All known myosins contain at least one such motif at their head-tail junctions; these IQ-motifs may function as calmodulin or light chain binding sites. The tail domain of chicken myosin-V consists of an initial 511 aa predicted to form several segments of coiled-coil alpha helix followed by a terminal 410-aa globular domain (aa, 1,421-1,830). Interestingly, a portion of the tail domain (aa, 1,094-1,830) shares 58% amino acid sequence identity with a 723-aa protein from mouse brain reported to be a glutamic acid decarboxylase. The neck region of chicken myosin-V, which contains the IQ-motifs, was demonstrated to contain the binding sites for CM by analyzing CM binding to bacterially expressed fusion proteins containing the head, neck, and tail domains. Immunolocalization of myosin-V in brain and in cultured cells revealed an unusual distribution for this myosin in both neurons and nonneuronal cells.(ABSTRACT TRUNCATED AT 400 WORDS)