Structure, glycosylation, and localization of rat intestinal guanylyl cyclase C: modulation by fasting.
Structure, glycosylation, and localization of rat intestinal guanylyl cyclase C: modulation by fasting.
复制标题
大鼠肠道鸟苷酸环化酶 C 的结构、糖基化和定位：禁食调节。
DOI：
10.1152/ajpgi.1996.271.6.g959
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Chong,KM
中科院分区：
文献类型：
--
作者：
Scheving,LA;Russell,WE;Chong,KM
鸟苷酸环化酶C(GC-C)是一种肠道受体鸟苷酸环化酶，与引起腹泻的细菌配体如大肠杆菌耐热肠毒素结合。我们研究了喂食和禁食对GC-C的表达、结构和生化特性的调节影响。当在非还原条件下在4℃下溶解时，来自喂食和禁食大鼠的GC-C都以两个极大的聚集体的形式在7%十二烷基硫酸钠-聚丙烯酰胺凝胶上迁移，几乎不能穿透堆积和分解凝胶。在喂食但不禁食的老鼠样本中，二硫键的化学还原分解了GC-C，导致其以较小的形式迁移(约220和240 kDa)。尽管禁食大鼠的GC-C聚集体抵抗了化学还原的这种解聚作用，但它们在重新进食后90分钟内迅速获得了这种聚集体。当在还原条件下在变性温度(95摄氏度)下溶解时，GC-C聚集体基本上分解成四个较小的蛋白质(相对分子质量约为140,000,131,000，85,000和65,000)。然而，在禁食的大鼠膜上，131 kDa的糖蛋白不成比例地增加。该单位和220 kDa单位对内切糖苷酶H敏感。亚细胞分级和免疫组织化学研究显示，禁食期间GC-C主要从表面重新分布到细胞内。
Guanylyl cyclase C (GC-C), an intestinal receptor guanylyl cyclase, binds diarrhea-producing bacterial ligands such as the Escherichia coli heat stable enterotoxin. We examined the regulatory influence of feeding and fasting on the expression, structure, and biochemical properties of GC-C. When solubilized at 4 degrees C under nonreducing conditions, GC-C from both fed and fasted rats migrated on 7% sodium dodecyl sulfate-polyacrylamide electrophoretic gels as two extremely large aggregates that barely penetrated the stacking and resolving gels. Chemical reduction of disulfide linkages disaggregated GC-C in fed but not fasted rat samples, causing it to migrate as smaller forms (approximately 220 and 240 kDa). Although GC-C aggregates from fasted rats resisted this disaggregating effect of chemical reduction, they rapidly acquired it within 90 min of refeeding. When solubilized at denaturing temperatures (95 degrees C) under reducing conditions, GC-C aggregates largely disassembled into four smaller proteins (relative molecular weight approximately 140,000, 131,000, 85,000, and 65,000). However, the 131-kDa glycoprotein was disproportionately increased in fasted rat membranes. This unit and the 220-kDa unit were sensitive to endoglycosidase H. Subcellular fractionation and immunohistochemical studies revealed a major redistribution of GC-C from surface to intracellular enterocyte sites during fasting.