Two eye guanylyl cyclases are expressed in the same photoreceptor cells and form homomers in preference to heteromers
Two eye guanylyl cyclases are expressed in the same photoreceptor cells and form homomers in preference to heteromers
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DOI：
10.1074/jbc.272.21.13738
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发表时间：
1997-05-23
影响因子：
4.8
通讯作者：
Garbers, DL
中科院分区：
文献类型：
--
作者：
Yang, RB;Garbers, DL
我们最近描述了两种眼鸟苷酸环化酶（GC-E和GC-F），其含有可能能够结合配体的表观胞外结构域（Yang，R. B.，福斯特，华盛顿特区，Garbers，D. L.，Fulle，H.- J，（1995）Proc.Natl. Acad. Sci.联合S. A. 92，602-606）。在这里，北方和西方的分析表明，这两个环化酶在视网膜中表达，并在感光细胞外节丰富。通过使用与不同大小的金颗粒偶联的特异性GC-E和GC-F抗体，两种环化酶共定位在相同的感光细胞内，提高了同聚和/或异聚相互作用的可能性。GC-E（D878 A）的点突变体的构建和表达，它不包含可检测的环化酶活性，但在显性负性的方式，以消除活动的天然GC-E和GC-F的共表达研究。这些结果表明，GC-E和GC-F可以形成同聚体或异聚体，至少当在COS-7细胞中过表达时。用GC-E和GC-F抗体进行免疫沉淀，然后进行Western分析，证实可以形成同聚体和异聚体。然而，使用视网膜或外节进行的类似实验显示，绝大多数GC-E和GC-F在眼中作为同聚体沉淀。因此，与膜鸟苷酸环化酶亚家族的其他成员一样，GC-E和GC-F似乎优先形成同聚体。
We recently described two eye guanylyl cyclases (GC-E and GC-F) that contain an apparent extracellular domain potentially capable of binding ligands (Yang, R.-B., Foster, D, C., Garbers, D. L., and Fulle, H.-J, (1995) Proc. Natl. Acad. Sci. U. S. A. 92, 602-606). Here, Northern and Western analyses showed that both cyclases are expressed in the retina and enriched in photoreceptor outer segments. By the use of specific GC-E and GC-F antibodies coupled to different sized gold particles both cyclases were colocalized within the same photoreceptor cells raising the possibility of homomeric and/or heteromeric interactions. A point mutant of GC-E (D878A) was constructed and expressed; it contained no detectable cyclase activity but acted in a dominant negative fashion to abolish the activity of native GC-E and GC-F in coexpression studies. These results suggested that GC-E and GC-F could form either homomers or heteromers, at least when overexpressed in COS-7 cells. Immunoprecipitation with GC-E and GC-F antibody followed by Western analysis confirmed that both homomers and heteromers could be formed. However, similar experiments using retina or outer segments revealed that a vast majority of GC-E and GC-F were precipitated as homomers in the eye. Therefore, like other members of the membrane guanylyl cyclase subfamily, GC-E and GC-F appear to preferentially form homomers.