Muramoto S, Murakami T, Urasawa K, Kawaguchi H, Kitabatake A
Department of Cardiovascular Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
Biochem Biophys Res Commun. 1995 Jan 17;206(2):799-804. doi: 10.1006/bbrc.1995.1113.
The expression of three different subtypes of GTP binding protein beta-subunits (beta 1, beta 2 and beta 3) was examined in rat hearts at both mRNA and protein levels. Among three subtypes, beta 3 mRNA was more abundant in ventricles while beta 1 and beta 2 mRNAs were expressed ubiquitously among ventricles, atria and aortas. The immunodetectable beta 1- and beta 3-proteins were predominantly found in the cytosolic fraction of rat ventricles. In this study, we demonstrate ventricle-specific expression of beta 3-subunit and localization of G protein beta 3-subunit in the cytosol of rat hearts. This unusual cytosolic localization of G protein beta 3-subunit might indicate subtype-specific function of G protein beta (gamma)-subunits in rat hearts.
在大鼠心脏中，从mRNA和蛋白质水平检测了三种不同亚型的GTP结合蛋白β亚基（β1、β2和β3）的表达。在这三种亚型中，β3 mRNA在心室中更为丰富，而β1和β2 mRNA在心室、心房和主动脉中均有广泛表达。免疫可检测到的β1和β3蛋白主要存在于大鼠心室的胞质部分。在本研究中，我们证明了β3亚基在大鼠心脏心室中的特异性表达以及G蛋白β3亚基在大鼠心脏胞质中的定位。G蛋白β3亚基这种不寻常的胞质定位可能表明G蛋白β（γ）亚基在大鼠心脏中具有亚型特异性功能。
