Feng J F, Rhee S G, Im M J
Department of Molecular Cardiology, Research Institute, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
J Biol Chem. 1996 Jul 12;271(28):16451-4. doi: 10.1074/jbc.271.28.16451.
A new class of GTP-binding protein transglutaminase II (Gh) couples to a 69-kDa phospholipase C (PLC). An 8-amino acid region (Leu665-Lys672) of the alpha-subunit of Gh (Galphah) is involved in interaction and activation of PLC, an observation that has now been used to characterize the 69-kDa PLC further. A 20-amino acid peptide corresponding to Leu654-Leu673 of Galphah was used to prepare an affinity resin. On incubation with a partially purified PLC preparation from rat liver membranes, the affinity resin-bound approximately69- and 85-kDa proteins were recognized by an antibody to the 69-kDa PLC. Both purified 69-kDa PLC and PLC-delta1 bound to the affinity resin; moreover, antibodies to PLC-delta1 recognized the 69-kDa PLC, and antibodies to the 69-kDa PLC recognized PLC-delta1. A synthetic peptide corresponding to Leu661-Lys672 of Galphah inhibited the binding of PLC-delta1 to the affinity resin and also stimulated PLC-delta1. Reconstitution of PLC-delta1 with GTPgammaS (guanosine 5'-3-O-(thio)triphosphate)-activated Gh resulted in activation of PLC-delta1. Antibodies to Galphah also coimmunoprecipitated PLC-delta1 upon activation of Gh. These findings indicate that PLC-delta1 is the effector of Gh-mediated signaling.
一类新的GTP结合蛋白转谷氨酰胺酶II（Gh）与一种69 kDa的磷脂酶C（PLC）偶联。Gh的α亚基（Galphah）的一个8氨基酸区域（Leu665 - Lys672）参与PLC的相互作用和激活，这一观察结果现在已被用于进一步表征69 kDa的PLC。对应于Galphah的Leu654 - Leu673的一个20氨基酸肽被用于制备亲和树脂。在用大鼠肝膜的部分纯化PLC制剂孵育时，亲和树脂结合的约69 kDa和85 kDa蛋白可被抗69 kDa PLC的抗体识别。纯化的69 kDa PLC和PLC - δ1都与亲和树脂结合；此外，抗PLC - δ1的抗体识别69 kDa PLC，抗69 kDa PLC的抗体识别PLC - δ1。对应于Galphah的Leu661 - Lys672的合成肽抑制PLC - δ1与亲和树脂的结合，并且还刺激PLC - δ1。用GTPγS（鸟苷5'-3 - O -（硫代）三磷酸）激活的Gh对PLC - δ1进行重组导致PLC - δ1激活。激活Gh后，抗Galphah的抗体也能共免疫沉淀PLC - δ1。这些发现表明PLC - δ1是Gh介导信号传导的效应器。
