Noda C, Tanahashi N, Shimbara N, Hendil K B, Tanaka K
Hyogo College, Kakogawa, Hyogo, 675-0101, Japan.
Biochem Biophys Res Commun. 2000 Oct 22;277(2):348-54. doi: 10.1006/bbrc.2000.3676.
We investigated the expression of standard proteasomes, immunoproteasomes, and their regulators, PA28, and PA700, in rat tissues. Immunoproteasomes (with subunits LMP2, LMP7, and MECL1) were abundant in the spleen but almost absent in the brain. In contrast, standard proteasomes (with X, Y, and Z) were highly expressed in the brain but not in the spleen. Both proteasome types were present in the lung and the liver. PA700 subunits (p112, S5a, and p45) were found in all tissues. PA28alpha, PA28beta, and PA28gamma were also expressed in all tissues, except for the brain which contained very little PA28beta. The results did not depend on rat sex or age. The cleavage specificity for peptide substrates differed greatly between brain and spleen proteasomes. Hybrid proteasomes, containing both PA28alphabeta and PA700, were not present in the brain but in all other tissues examined.
我们研究了标准蛋白酶体、免疫蛋白酶体及其调节因子PA28和PA700在大鼠组织中的表达情况。免疫蛋白酶体（含亚基LMP2、LMP7和MECL1）在脾脏中含量丰富，但在大脑中几乎不存在。相比之下，标准蛋白酶体（含X、Y和Z亚基）在大脑中高表达，但在脾脏中不表达。两种类型的蛋白酶体在肺和肝脏中均有存在。PA700亚基（p112、S5a和p45）在所有组织中均有发现。PA28α、PA28β和PA28γ在所有组织中也均有表达，但大脑中PA28β含量极少。结果不受大鼠性别或年龄的影响。大脑和脾脏蛋白酶体对肽底物的切割特异性差异很大。含有PA28αβ和PA700的杂合蛋白酶体在大脑中不存在，但在所检测的所有其他组织中均有存在。
