A unique family of proteins associated with internalized membranes in protein storage vacuoles of the Brassicaceae
A unique family of proteins associated with internalized membranes in protein storage vacuoles of the Brassicaceae
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DOI：
10.1111/j.1365-313x.2004.02303.x
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发表时间：
2005-02-01
期刊：
影响因子：
7.2
通讯作者：
Rogers, JC
中科院分区：
文献类型：
--
作者：
Gillespie, J;Rogers, SW;Rogers, JC
蛋白质储存液泡(PSV)是植物种子中的一个特殊细胞器，在种子发育过程中积累储存蛋白质和植酸。在许多植物中，如番茄和烟草，PSV含有两种类型的显微可见的细胞器内包裹体：由膜和蛋白质组成的大晶格，晶体，以及一个或几个大的植酸盐晶体，球体。在十字花科的种子中，PSV缺乏可见的晶体，有许多散布在各处的小球体。我们对甘蓝型油菜中的PSV进行了生化分离，并定义了一种晶体状组分，它包含了在其他植物的晶体中发现的完整的膜蛋白标记物。蛋白质分析确定了一个以前未被描述的蛋白质家族，即十字花科PSV-Embedded Proteins(BPEPs)，与‘晶体’和球状组分相关。BPEP的定义特征是N-末端信号肽和串联的数学结构域，它们可能介导蛋白质-蛋白质的相互作用。数据库分析表明，BPEP是十字花科所特有的。免疫荧光研究使用抗BPEP抗体和其他生化标记物的抗体标记油菜和拟南芥种子切片，将BPEP定位于PSV内的结构，其外观与内化膜和球体的扩散网络一致。这些结果表明，十字花科植物的PSV含有内化的膜，并增加了BPEP改变这些内部膜结构以产生不同于番茄或烟草的PSV形态的可能性。
The protein storage vacuole (PSV) is a specialized organelle in plant seeds that accumulates storage proteins and phytate during seed development. In many plant species, such as tomato and tobacco, the PSV contains two types of microscopically visible intra-organellar inclusions: a large crystalline lattice of membranes and proteins, the crystalloid, and one or a few large phytate crystals, the globoids. In seeds of the family Brassicaceae, the PSVs lack visible crystalloids and have many small globoids dispersed throughout. We biochemically fractionated PSVs from Brassica napus and defined a crystalloid-like fraction that contained integral membrane protein markers found in crystalloids of other plants. Protein analyses identified a previously undescribed family of proteins, the Brassicaceae PSV-embedded proteins (BPEPs), associated with 'crystalloid' and globoid fractions. The defining characteristics of the BPEPs are an N-terminal signal peptide and tandem MATH domains, which may mediate protein-protein interactions. Database analyses indicated that the BPEPs are unique to Brassicaceae. Immunofluorescence studies using anti-BPEP antibodies and antibodies to other biochemical markers to label B. napus and Arabidopsis thaliana seed sections localized the BPEPs to structures within the PSVs, whose appearance was consistent with a diffuse network of internalized membranes and globoids. These results demonstrate that Brassicaceae PSVs contain internalized membranes, and raise the possibility that BPEPs modify these internal membrane structures to yield a PSV morphology different from that of tomato or tobacco.