THE ULTRASTRUCTURAL LOCATION OF C-PROTEIN, X-PROTEIN AND H-PROTEIN IN RABBIT MUSCLE
THE ULTRASTRUCTURAL LOCATION OF C-PROTEIN, X-PROTEIN AND H-PROTEIN IN RABBIT MUSCLE
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DOI：
10.1007/bf01753571
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发表时间：
1986-12-01
影响因子：
2.7
通讯作者：
OFFER, G
中科院分区：
文献类型：
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作者：
BENNETT, P;CRAIG, R;OFFER, G
用粗丝辅助蛋白C蛋白、X蛋白和H蛋白的纯化抗体标记了兔腰肌(主要含快白纤维)、比目鱼肌(主要含慢红纤维)和足底肌(一种混合纤维型肌肉)的纤维，并用电子显微镜观察了它们的位置。这些辅助蛋白存在于一组11条横纹中的一条或多条上，这些横纹相距约43 nm，以前在每个半A带中都观察到了这些横纹。每种蛋白质都有一组有限的特征分布。在大多数腰肌纤维中，H蛋白存在于3号条纹上(从M线开始计算)，但在比目鱼肌和足底肌中不存在。C-蛋白可出现在(1)4-11(腰大肌中最常见的模式)上；(2)5-11(腰大肌和足底)上；(3)3和5-11(足底)上；或(4)不出现在任何地方(在所有三块肌肉的红色纤维中)。X蛋白可出现在(1)所有三块肌肉的红色纤维的3-11条上；(2)仅在4条(腰大肌和足底肌中)；(3)3和4条(在腰大肌和足底肌中)；或(4)在没有的情况下。用抗-X标记的条纹比用抗-C标记的条纹更宽，并且由一个内部间距为16 nm的二重体组成。这三种辅助蛋白的模式虽然重叠，但在任何情况下都不是完全相同的，这表明这三种蛋白并不是简单地相互替代。抗C标记的条纹与抗X条纹的轴向位置不同；抗X条纹比相应的抗C条纹距离M线的距离约8-9 nm。这意味着X蛋白双重体的内部成员位于与C蛋白条带非常相似的位置。在大多数腰肌纤维中看到的抗H标记的条纹比腰大肌红色纤维中的抗X标记的条纹3更接近M线14 nm，并且与C蛋白阵列的延续交错了约4 nm。标记图案在纤维内保持不变，表明了一种非常精确的组装机制。由存在的辅助蛋白质及其排列所定义的纤维类别的数量超过了目前公认的纤维类型的数量。
Purified antibodies to the thick filament accessory proteins, C-protein, X-protein and H-protein, have been used to label fibres of three rabbit muscles, psoas (containing mainly fast white fibres), soleus (containing mainly slow red fibres) and plantaris (a muscle of mixed fibre type) and their location has been examinedy by electron microscopy. These accessory proteins are present on one or more of a set of eleven transverse stripes about 43 nm apart that have been observed previously in each half A-band. Each protein has a limited set of characteristic distributions. H-protein is present on stripe 3 (counting from the M-line) in the majority of psoas fibres but is absent in soleus and plantaris muscle. C-protein can occur (1) on stripes 4-11 (the commonest pattern seen in psoas); (2) on stripes 5-11 (in psoas and plantaris); (3) on stripe 3 together with stripes 5-11 (in plantaris); or (4) on none (in red fibres of all three muscles). X-protein can occur (1) on stripes 3-11 in the red fibres of all three muscles; (2) on stripe 4 only ( in psoas and plantaris); (3) on stripes 3 and 4 (in psoas and plantaris) or (4) on none. Stripes labelled with anti-X are wider than those labelled with anti-C and consist of a doublet with an internal spacing of 16 nm. The patterns for the three accessory proteins, while overlapping, are in no case identical, this suggests the proteins do not simply substitute for one another. The precise axial positions of the anti-C labelled stripes differ from those of the anti-X stripes; the anti-X stripes lie about 8-9 nm further from the M-line than the corresponding anti-C stripes. This implies that the inner member of an X-protein doublet lies in a very similar position to a C-protein stripe. The anti-H labelled stripe seen in most psoas fibres lies 14 nm nearer the M-line than stripe 3 of the anti-X labelled array in psoas red fibres and is staggered from a continuation of the C-protein array by about 4nm. The labelling patterns were constatn within a fibre and suggest a very precise-assembly mechanism. The number of classes of fibre, as defined by the accessory proteins present and their arrangement, exceeds the number of fibre types presently recognized.