An Arabidopsis protein with a novel calcium-binding repeat sequence interacts with TONSOKU/MGOUN3/BRUSHY1 involved in meristem maintenance.
An Arabidopsis protein with a novel calcium-binding repeat sequence interacts with TONSOKU/MGOUN3/BRUSHY1 involved in meristem maintenance.
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DOI：
10.1093/pcp/pci155
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发表时间：
2005-09
影响因子：
4.9
通讯作者：
Takamasa Suzuki;Sakiko Nakajima;A. Morikami;K. Nakamura
中科院分区：
文献类型：
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作者：
Takamasa Suzuki;Sakiko Nakajima;A. Morikami;K. Nakamura
来自拟南芥的TONSOKU（TSK）/MGOUN 3/BRUSHY 1在分生组织的维持中起重要作用，其包含与在参与不对称细胞分裂的动物蛋白中发现的相似的LGN重复基序。在酵母双杂交筛选中与TSK的LGN基序相互作用的一种蛋白质TSK相关蛋白1（TSA 1）含有独特的41个氨基酸序列的10倍重复。具有谷氨酸-苯丙氨酸-谷氨酸（EFE）保守核心序列的重复序列富含酸性氨基酸。TSA 1还含有一个N-末端推定的信号肽，它通过一个C-末端区域与TSK的LGN基序相互作用，该C-末端区域与EFE重复序列之间被一个推定的跨膜区域隔开。重组蛋白由EFE重复序列组成，具有丰富的α-螺旋结构，并具有钙离子结合活性。与TSK的核定位不同，在烟草BY-2细胞中表达的与绿色荧光蛋白（GFP）融合的TSA 1在间期定位于小的胞质囊泡中。然而，TSA 1-GFP和GFP-TSK的细胞定位在有丝分裂期间动态变化。特别是，GFP-TSK和TSA 1-GFP都集中在有限的区域，靠近纺锤体微管的末端，在分离染色单体之前。这些结果进行了讨论，TSK和TSA 1在有丝分裂的可能参与。
TONSOKU(TSK)/MGOUN3/BRUSHY1 from Arabidopsis thaliana, which plays an important role in the maintenance of meristem organization, contains an LGN repeat motif similar to that found in animal proteins involved in asymmetric cell division. One protein that interacts with the LGN motif of TSK in a yeast two-hybrid screen, TSK-associating protein 1 (TSA1), contains a 10-fold repeat of a unique 41 amino acid sequence. The repeat sequence, with a glutamic acid-phenylalanine-glutamic acid (EFE) conserved core sequence, is enriched with acidic amino acids. TSA1 also contains an N-terminal putative signal peptide and it interacts with the LGN motif of TSK through a C-terminal region separated from the EFE repeats by a putative membrane-spanning region. The recombinant protein consisting of EFE repeats was rich in alpha-helical structure and possessed Ca2+-binding activity. Unlike nuclear localization of TSK, the TSA1 fused with green fluorescent protein (GFP) expressed in tobacco BY-2 cells was localized in small cytoplasmic vesicles during interphase. However, cellular localization of both TSA1-GFP and GFP-TSK changed dynamically during mitosis. In particular, both GFP-TSK and TSA1-GFP were concentrated in limited areas that are close to the ends of spindle microtubules ahead of separating chromatids. These results are discussed in terms of the possible involvement of TSK and TSA1 in mitosis.