Department of Biology, Brooklyn College of the City University of New York, 11210, USA.
Cytoskeleton (Hoboken). 2010 Feb;67(2):90-101. doi: 10.1002/cm.20426.
Previous studies have shown that Myo1(myosin class XIV) localizes to the cytoskeleton and is involved in amitosis of the macronucleus and trafficking of phagosomes. Myo1 contains a FERM domain that could be a site for interaction between Myo1 and the cytoskeleton. Here, we explore the function of FERM by investigating its cytoskeleton binding partners and involvement in localization of Myo1. Alignment of Myo1 FERM with a talin actin-binding sequence, a MAP-2 tubulin-binding sequence, the radixin FERM dimerization motif, and the SV40 nuclear localization sequence (NLS) revealed putative actin- and tubulin-binding sequences, a putative FERM dimerization motif, and NLS-like sequences in both the N-terminal and C-terminal regions of Myo1 FERM. Alignment of Myo1 with an ERM C-terminal motif revealed a similar sequence in the Myo1 motor domain. GFP-FERM and two truncated FERM domains were separately expressed in Tetrahymena. GFP-FERM contained the entire Myo1 FERM. Truncated Myo1 FERM domains contained either the N-terminal or the C-terminal region of FERM and one putative sequence for actin-binding, one for tubulin-binding, a putative dimerization motif, and a NLS-like sequence. Actin antibody coprecipitated GFP-fusion polypeptides and tubulin from lysate of cells expressing GFP-fusions. Cosedimentation assays performed with either whole cell extracts or anti-actin immunoprecipitation pellets revealed that F-actin (independent of ATP) and microtubules cosedimented with GFP-fusion polypeptides. GFP-FERM localized to the cytoskeleton, phagosomes, and nucleus. Truncated GFP-FERM domains localized to phagosomes but not to the cytoskeleton or nucleus.
先前的研究表明，Myo1（肌球蛋白 XIV 类）定位于细胞骨架，参与大核的无丝分裂和吞噬体的运输。Myo1 含有一个 FERM 结构域，该结构域可能是 Myo1 与细胞骨架相互作用的部位。在这里，我们通过研究其细胞骨架结合伙伴和参与 Myo1 定位的功能，来探索 FERM 的功能。Myo1 FERM 与 talin 肌动蛋白结合序列、MAP-2 微管结合序列、radixin FERM 二聚化基序和 SV40 核定位序列（NLS）的对齐显示了潜在的肌动蛋白和微管结合序列、潜在的 FERM 二聚化基序以及 Myo1 FERM 的 N 端和 C 端区域中的 NLS 样序列。Myo1 与 ERM C 端基序的比对显示了 Myo1 运动域中的类似序列。GFP-FERM 和两个截断的 FERM 结构域分别在 Tetrahymena 中表达。GFP-FERM 包含整个 Myo1 FERM。截断的 Myo1 FERM 结构域包含 FERM 的 N 端或 C 端区域以及一个潜在的肌动蛋白结合序列、一个微管结合序列、一个潜在的二聚化基序和一个 NLS 样序列。肌动蛋白抗体从表达 GFP 融合物的细胞裂解物中沉淀 GFP 融合多肽和微管。用全细胞提取物或抗肌动蛋白免疫沉淀沉淀进行的共沉淀实验表明，F-肌动蛋白（独立于 ATP）和微管与 GFP 融合多肽共沉淀。GFP-FERM 定位于细胞骨架、吞噬体和细胞核。截断的 GFP-FERM 结构域定位于吞噬体，但不定位于细胞骨架或细胞核。
