EXPRESSION OF ENDOPLASMIC-RETICULUM CA-2+-PUMP ISOFORMS AND OF PHOSPHOLAMBAN IN PIG SMOOTH-MUSCLE TISSUES
EXPRESSION OF ENDOPLASMIC-RETICULUM CA-2+-PUMP ISOFORMS AND OF PHOSPHOLAMBAN IN PIG SMOOTH-MUSCLE TISSUES
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DOI：
10.1042/bj2710649
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发表时间：
1990-11-01
影响因子：
4.1
通讯作者：
CASTEELS, R
中科院分区：
文献类型：
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作者：
EGGERMONT, JA;WUYTACK, F;CASTEELS, R
研究了基因2肌浆/内质网Ca2+泵同工型（SERCA2a和SERCA2b）和磷蛋白在猪胃平滑肌、纵向回肠、肺动脉和主动脉中的表达。采用RNAase保护实验测定mRNA水平。SERCA2亚型和磷蛋白在Western blots上用一组抗体进行检测，其中一些抗体是亚型特异性的。猪平滑肌组织都含有相似的SERCA2 mRNA水平，但这些水平比心肌中的SERCA2 mRNA水平低10-20倍。在平滑肌中的SERCA2 mrna中，72-81%编码非肌肉亚型（SERCA2b），使用同种型特异性抗体的Western blot分析证实，SERCA2b亚型是平滑肌中主要的内质网Ca2+泵。与SERCA2 mRNA水平相比，不同猪平滑肌组织中磷蛋白mRNA水平相差12倍，猪肺动脉和猪主动脉中的磷蛋白水平分别较低和极低。蛋白印迹也证实了磷蛋白的差异表达。研究发现，在不同的平滑肌组织中，磷蛋白含量不同，而SERCA2的表达保持不变，这表明，在猪平滑肌中，磷蛋白的表达不与SERCA2的表达偶联。
The expression of the gene 2 sarcoplasmic/endoplasmic-reticulum Ca2+-pump isoforms (SERCA2a and SERCA2b) and of phospholamban was studied in pig smooth muscle of the stomach, longitudinal ileum, pulmonary artery and aorta. mRNA levels were determined using an RNAase protection assay. The SERCA2 isoforms and phospholamban were tested on Western blots with a panel of antibodies, some of which were isoform-specific. The pig smooth-muscle tissues all contained comparable SERCA2 mRNA levels, but these levels were 10-20-fold lower than SERCA2 mRNA levels in cardiac muscle. Of the SERCA2 mRNAs in smooth muscle, 72-81% encoded the non-muscle isoform (SERCA2b), and Western blot analysis with isoform-specific antibodies confirmed that the SERCA2b isoform is the predominant endoplasmic-reticulum Ca2+ pump in smooth muscle. In contrast with SERCA2 mRNA levels, phospholamban mRNA levels varied by 12-fold between the different pig smooth-muscle tissues, with low and very low levels in the pig pulmonary artery and the pig aorta respectively. The differential expression of phospholamban was also confirmed on Western blots. The finding that the phospholamban content varied between the different smooth-muscle tissues whereas the SERCA2 expression remained rather constant indicates that, in pig smooth muscle, the expression of phospholamban is not coupled with that of SERCA2.