Analysis of a lympho-hematopoietic specific nuclear protein with homology to RaplGAP

与 RaplGAP 同源的淋巴造血特异性核蛋白的分析

• 批准号: 05670300
• 负责人: HATTORI Masakazu
• 金额: $ 1.41万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05670300/
• 关键词: RanGAP; RaplGAP; nuclear protein; cell cycle progression; Ran; RCC-1 system; Interleukin-2; differntial hybridization; Ran GAP; 有糸分裂破綻; リン酸化会合分子; 細胞周期; Rap1GAPホモログ; 翻訳時ホッピング; GAP活性; 細胞増殖抑制

We have cloned a novel cDNA (Spa-1) which was little expressed in the quiescent state but induced in the interleukin 2 (IL2) -stimulated cycling state of an IL2-responsive murine lymphoid cell line by differential hybridization. Spa-1 mRNA (3.5kb) was induced in the normal lymphocytes following various mitogenic stimulation. In normal organs it was preferentially expressed in both fetal and adult lymphohematopoietic tissues. A Spa-1-coded protein of 68 kDa was localized mostly in the nucleus. Its N-terminal domain is highly homologous to a human Rapl GTPase activating protein (GAP) , and a fusion protein of this domain (SpanN) indeed exhibited GAP activity for Rapl/Rsrl but not for Ras or Rho in vitro. Unlike the human Rapl GAP,however, SpanN also exhibited GAP activity for Ran, so far the only known Ras-related GTPase in the nucleus. In the presence of serum, stable Spa-1 cDNA transfectants of NIH3T3 (NIH/Spa-1) hardly overexpressed Spa-1 (p68) and grew normally as the parental cells. When NIH/Spa-1 cells were serum-starved to be arrested in G1/0, however, they exhibited progressive Spa-1 p68 accumulation unlike the control cells, and following the addition of serum they showed cell death resembling mitotic catastrophes of S phase during cell cycle progression. The results indicates that the novel nuclear protein, Spa-1, with a potentially active Ran GAP domain severely hampers the mitogen-induced cell cycle progression when abnormally and/or prematurely expressed. Functions of the Spa-1 protein and its regulation are discussed in the context of its possible interaction with Ran/RCC-1 system, which is involved in the coordinated nuclear functions including cell division.

我们克隆了一种新的cDNA (Spa-1)，它在静止状态下很少表达，但在白细胞介素2 （IL2）刺激的循环状态下被诱导。在各种有丝分裂刺激下，正常淋巴细胞中诱导出3.5kb的Spa-1 mRNA。在正常器官中，它优先在胎儿和成人淋巴造血组织中表达。一个68 kDa的spa -1编码蛋白主要定位于细胞核。它的n端结构域与人Rapl GTPase激活蛋白（GAP）高度同源，该结构域的融合蛋白（SpanN）在体外确实对Rapl/Rsrl具有GAP活性，但对Ras或Rho没有GAP活性。然而，与人类Rapl的GAP不同，SpanN也表现出Ran的GAP活性，Ran是迄今为止已知的细胞核中唯一与ras相关的GTPase。在血清存在的情况下，稳定的NIH3T3 (NIH/Spa-1) cDNA转染体几乎没有过度表达Spa-1 (p68)，并作为亲本细胞正常生长。然而，当NIH/Spa-1细胞在G1/0中被血清饥饿时，它们表现出与对照细胞不同的渐进式Spa-1 p68积累，并且在添加血清后，它们在细胞周期进程中表现出类似于S期有丝分裂灾难的细胞死亡。结果表明，具有潜在活性Ran GAP结构域的新型核蛋白Spa-1在异常和/或过早表达时严重阻碍了丝裂原诱导的细胞周期进程。Spa-1蛋白的功能及其调控在其可能与Ran/RCC-1系统相互作用的背景下进行了讨论，该系统参与包括细胞分裂在内的协调核功能。

项目成果

H.Kubota,et al.: "Involvement of 4F2 antigen expressed on the MHC-negative target celle in the recognition of murine CD3^+4^-8^-αβ(Vα4/Vβ2)T celle." International Immunalogy. 6. 1323-1331 (1994)

H.Kubota 等人：“MHC 阴性靶细胞上表达的 4F2 抗原参与识别小鼠 CD3^+4^-8^-αβ(Vα4/Vβ2)T 细胞。” 1323-1331 (1994)

H.Kubota, et al.: "Involvement of 4F2 antigen expressed on the MHC-negative target cells in the recognition of murine CD3^+4^-8^-alphabeta (Valpha4/Vbeta2) T cells." International Immunology. 6. 1323-1331 (1994)

H.Kubota 等人：“MHC 阴性靶细胞上表达的 4F2 抗原参与识别鼠 CD3^4^-8^-alphabeta (Valpha4/Vbeta2) T 细胞。”

Hiroshi Kubota: "Involvement of 4F2 antigen expressed on the MHC-negative target cells in the recognition of murine CD3^+ CD4^- CD8^- αB(Vα_4/Vβ_2)T cells." International Immunology. 6. 1323-1331 (1994)

Hiroshi Kubota：“MHC 阴性靶细胞上表达的 4F2 抗原参与识别小鼠 CD3^+ CD4^- CD8^- αB(Vα_4/Vβ_2)T 细胞。”国际免疫学 6. 1323-1331。 ）

M.Hattori, et al.: "Molecular cloning of a novel mitogen-inducible nuclear protein with a Ran Gase-activating domain that affects cell cycle progression." Molecular and Cellular Biology.15. 552-560 (1995)

M.Hattori 等人：“分子克隆一种新型有丝分裂原诱导核蛋白，其具有影响细胞周期进程的 Ran Gase 激活结构域。”

M.Hattori,et al.: "Molecular cloning of a novel mitogen-inducible nuclear protein with a Ran GTPase-activating domain that affects cell cycle progression." Molecular and Cellular Biology. 15. 552-560 (1995)

M.Hattori 等人：“分子克隆一种新型有丝分裂原诱导核蛋白，其具有影响细胞周期进程的 Ran GTP 酶激活结构域。”