Trypanosoma brucei transferrin receptor: Functional replacement of the GPI anchor with a transmembrane domain
Trypanosoma brucei transferrin receptor: Functional replacement of the GPI anchor with a transmembrane domain
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DOI：
10.1016/j.molbiopara.2021.111361
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发表时间：
2021-01-18
影响因子：
1.5
通讯作者：
Steverding, Dietmar
中科院分区：
文献类型：
--
作者：
Kabiri, Mostafa;Steverding, Dietmar
布氏锥虫转铁蛋白受体（TbTfR）是糖基磷脂酰肌醇（GPI）锚定的ESAG6亚基和ESAG7亚基的异二聚体。为了研究GPI锚定是否对TbTfR的功能是必需的，在血流形式的锥虫中诱导表达具有跨膜结构域而不是GPI锚定的ESAG6（ESAG6tmd）。结果表明，ESAG6tmd能够与ESAG7二聚化，形成可以结合转铁蛋白的TbTfR。分馏实验清楚地表明，跨膜锚定TbTfR是专门与膜馏分。在转铁蛋白的摄取中，在诱导表达跨膜锚定TbTfR的锥虫和诱导表达GPI锚定TbTfR的锥虫之间没有观察到差异。ESAG6tmd和天然ESAG6糖基化模式的差异可能表明跨膜和GPI锚定的TbTfR的不同细胞内运输。这些结果表明，GPI锚对于TbTfR在T细胞血流形式中的功能不是必需的。布鲁塞。
The transferrin receptor of Trypanosoma brucei (TbTfR) is a heterodimer of a glycosylphosphatidylinositol (GPI)anchored ESAG6 subunit and an ESAG7 subunit. To investigate whether the GPI-anchor is essential for the function of the TbTfR, an ESAG6 with a transmembrane domain instead of a GPI-anchor (ESAG6tmd) was inducibly expressed in bloodstream form trypanosomes. It is shown that the ESAG6tmd is able to dimerise with ESAG7 to form a TbTfR that can bind transferrin. Fractionation experiments clearly demonstrated that the transmembrane-anchored TbTfR is exclusively associated with the membrane fraction. No difference in the uptake of transferrin was observed between trypanosomes inducibly expressing a transmembrane-anchored TbTfR and trypanosomes inducibly expressing a GPI-anchored TbTfR. Differences in glycosylation pattern of ESAG6tmd and native ESAG6 may indicate different intracellular trafficking of transmembrane- and GPI-anchored TbTfRs. The findings suggest that the GPI-anchor is not essential for the function of the TbTfR in bloodstream forms of T. brucei.