Independent Transport and Sorting of Functionally Distinct Protein Families in Tetrahymena thermophila Dense Core Secretory Granules
文献类型：期刊论文
| 作者 | Rahaman, Abdur1; Miao, Wei2; Turkewitz, Aaron P.1 |
| 刊名 | EUKARYOTIC CELL
 |
| 出版日期 | 2009-10-01 |
| 卷号 | 8期号:10页码:1575-1583 |
| 关键词 | PARAMECIUM MATURATION MUTANTS LATTICE POLYPEPTIDES TRICHOCYSTS EXOCYTOSIS EXPRESSION GENES CELLS |
| ISSN号 | 1535-9778 |
| 通讯作者 | Turkewitz, AP, Univ Chicago, Dept Mol Genet & Cell Biol, 920 E 58th St, Chicago, IL 60637 USA |
| 中文摘要 | Dense core granules (DCGs) in Tetrahymena thermophila contain two protein classes. Proteins in the first class, called granule lattice (Grl), coassemble to form a crystalline lattice within the granule lumen. Lattice expansion acts as a propulsive mechanism during DCG release, and Grl proteins are essential for efficient exocytosis. The second protein class, defined by a C-terminal beta/gamma-crystallin domain, is poorly understood. Here, we have analyzed the function and sorting of Grt1p (granule tip), which was previously identified as an abundant protein in this family. Cells lacking all copies of GRT1, together with the closely related GRT2, accumulate wild-type levels of docked DCGs. Unlike cells disrupted in any of the major GRL genes, Delta GRT1 Delta GRT2 cells show no defect in secretion, indicating that neither exocytic fusion nor core expansion depends on GRT1. These results suggest that Grl protein sorting to DCGs is independent of Grt proteins. Consistent with this, the granule core lattice in Delta GRT1 Delta GRT2 cells appears identical to that in wild-type cells by electron microscopy, and the only biochemical component visibly absent is Grt1p itself. Moreover, gel filtration showed that Grl and Grt proteins in cell homogenates exist in nonoverlapping complexes, and affinity-isolated Grt1p complexes do not contain Grl proteins. These data demonstrate that two major classes of proteins in Tetrahymena DCGs are likely to be independently transported during DCG biosynthesis and play distinct roles in granule function. The role of Grt1p may primarily be postexocytic; consistent with this idea, DCG contents from Delta GRT1 Delta GRT2 cells appear less adhesive than those from the wild type. |
| 英文摘要 | Dense core granules (DCGs) in Tetrahymena thermophila contain two protein classes. Proteins in the first class, called granule lattice (Grl), coassemble to form a crystalline lattice within the granule lumen. Lattice expansion acts as a propulsive mechanism during DCG release, and Grl proteins are essential for efficient exocytosis. The second protein class, defined by a C-terminal beta/gamma-crystallin domain, is poorly understood. Here, we have analyzed the function and sorting of Grt1p (granule tip), which was previously identified as an abundant protein in this family. Cells lacking all copies of GRT1, together with the closely related GRT2, accumulate wild-type levels of docked DCGs. Unlike cells disrupted in any of the major GRL genes, Delta GRT1 Delta GRT2 cells show no defect in secretion, indicating that neither exocytic fusion nor core expansion depends on GRT1. These results suggest that Grl protein sorting to DCGs is independent of Grt proteins. Consistent with this, the granule core lattice in Delta GRT1 Delta GRT2 cells appears identical to that in wild-type cells by electron microscopy, and the only biochemical component visibly absent is Grt1p itself. Moreover, gel filtration showed that Grl and Grt proteins in cell homogenates exist in nonoverlapping complexes, and affinity-isolated Grt1p complexes do not contain Grl proteins. These data demonstrate that two major classes of proteins in Tetrahymena DCGs are likely to be independently transported during DCG biosynthesis and play distinct roles in granule function. The role of Grt1p may primarily be postexocytic; consistent with this idea, DCG contents from Delta GRT1 Delta GRT2 cells appear less adhesive than those from the wild type. |
| WOS标题词 | Science & Technology ; Life Sciences & Biomedicine |
| 学科主题 | Microbiology |
| 类目[WOS] | Microbiology |
| 研究领域[WOS] | Microbiology |
| 关键词[WOS] | PARAMECIUM ; MATURATION ; MUTANTS ; LATTICE ; POLYPEPTIDES ; TRICHOCYSTS ; EXOCYTOSIS ; EXPRESSION ; GENES ; CELLS |
| 收录类别 | SCI |
| 资助信息 | National Institutes of Health [GM077607] |
| 语种 | 英语 |
| WOS记录号 | WOS:000270399300011 |
| 公开日期 | 2010-10-13 |
| 源URL | [http://ir.ihb.ac.cn/handle/152342/7570]  |
| 专题 | 水生生物研究所_中科院水生所知识产出（2009年前）_期刊论文 |
| 作者单位 | 1.Univ Chicago, Dept Mol Genet & Cell Biol, Chicago, IL 60637 USA 2.Chinese Acad Sci, Inst Hydrobiol, Wuhan, Peoples R China |
| 推荐引用方式 GB/T 7714 | Rahaman, Abdur,Miao, Wei,Turkewitz, Aaron P.. Independent Transport and Sorting of Functionally Distinct Protein Families in Tetrahymena thermophila Dense Core Secretory Granules[J]. EUKARYOTIC CELL,2009,8(10):1575-1583. |
| APA | Rahaman, Abdur,Miao, Wei,&Turkewitz, Aaron P..(2009).Independent Transport and Sorting of Functionally Distinct Protein Families in Tetrahymena thermophila Dense Core Secretory Granules.EUKARYOTIC CELL,8(10),1575-1583. |
| MLA | Rahaman, Abdur,et al."Independent Transport and Sorting of Functionally Distinct Protein Families in Tetrahymena thermophila Dense Core Secretory Granules".EUKARYOTIC CELL 8.10(2009):1575-1583. |
入库方式： OAI收割
来源：水生生物研究所
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