Sequences, structural models, and cellular localization of the actin-related proteins Arp2 and Arp3 from Acanthamoeba.
Sequences, structural models, and cellular localization of the actin-related proteins Arp2 and Arp3 from Acanthamoeba.
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DOI：
10.1083/jcb.131.2.385
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发表时间：
1995-10
期刊：
影响因子：
--
通讯作者：
Pollard TD
中科院分区：
文献类型：
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作者：
Kelleher JF;Atkinson SJ;Pollard TD
我们克隆并测序了棘阿米巴的两个肌动蛋白相关蛋白（Arps） （Machesky， L. M.， S. J. Atkinson， C. Ampe， J. Vandekerckhove， T. D. Pollard. 1994，细胞生物学杂志127:107-115）。Arp2序列与其他Arp3序列的相似性大于与actin序列的相似性，而Arp3序列与其他Arp3序列的相似性大于与actin序列的相似性。所有已知的Arps的系统发育分析表明，大多数Arps可分为三大家族，这可能是所有真核生物门共有的。与传统的肌动蛋白一起，Arps形成了一个更大的家族，不同于结构相关的atp酶，如Hsp70和糖激酶。基于Arps序列和肌动蛋白结构的原子模型为其功能提供了一些线索。两种Arps都有合适的原子来结合ATP和二价阳离子。Arp2，而不是Arp3，有一个保守的profile -binding位点。这两种Arp都没有与肌动蛋白共聚所需的残基，但存在于侧链结合复合物中的Arp异二聚体可能作为肌动蛋白聚合的尖端核。两种棘阿米巴Arps均可溶于细胞匀浆，且均集中于棘阿米巴皮层。细胞浓度为1.9微米Arp2和5.1微米Arp3，亚化学计量与肌动蛋白（200微米）相当，但与许多肌动蛋白结合蛋白相当。
We cloned and sequenced the two actin-related proteins (Arps) present in the profilin-binding complex of Acanthamoeba (Machesky, L. M., S. J. Atkinson, C. Ampe, J. Vandekerckhove, and T. D. Pollard. 1994, J. Cell Biol. 127:107-115). The sequence of Arp2 is more similar to other Arp2s than to actin, while the sequence of Arp3 is more similar to other Arp3s than to actin. Phylogenetic analysis of all known Arps demonstrates that most group into three major families, which are likely to be shared across all eukaryotic phyla. Together with conventional actins, the Arps form a larger family distinct from structurally related ATPases such as Hsp70's and sugar kinases. Atomic models of the Arps based on their sequences and the structure of actin provide some clues about function. Both Arps have atoms appropriately placed to bind ATP and divalent cation. Arp2, but not Arp3, has a conserved profilin-binding site. Neither Arp has the residues required to copolymerize with actin, but an Arp heterodimer present in the profilin-binding complex might serve as a pointed end nucleus for actin polymerization. Both Acanthamoeba Arps are soluble in cell homogenates, and both are concentrated in the cortex of Acanthamoeba. The cellular concentrations are 1.9 microM Arp2 and 5.1 microM Arp3, substoichiometric to actin (200 microM) but comparable to many actin- binding proteins.