Stumpf Maria, Müller Rolf, Gaßen Berthold, Wehrstedt Regina, Fey Petra, Karow Malte A, Eichinger Ludwig, Glöckner Gernot, Noegel Angelika A
Institute of Biochemistry I, Medical Faculty, University Hospital Cologne, Center for Molecular Medicine Cologne, University of Cologne, Joseph-Stelzmann-Str. 52, Köln 50931, Germany.
Dicty Base, Northwestern University, Biomedical Informatics Center and Center for Genetic Medicine, Chicago, IL 60611, USA.
Dis Model Mech. 2017 Jul 1;10(7):897-907. doi: 10.1242/dmm.029280. Epub 2017 May 25.
Mutations in tripeptidyl peptidase 1 () have been associated with late infantile neuronal ceroid lipofuscinosis (NCL), a neurodegenerative disorder. TPP1 is a lysosomal serine protease, which removes tripeptides from the N-terminus of proteins and is composed of an N-terminal prodomain and a catalytic domain. It is conserved in mammals, amphibians, fish and the amoeba harbors at least six genes encoding TPP1, to We identified TPP1F as binding partner of GPHR (Golgi pH regulator), which is an evolutionarily highly conserved intracellular transmembrane protein. A region encompassing the DUF3735 (GPHR_N) domain of GPHR was responsible for the interaction. In TPP1F, the binding site is located in the prodomain of the protein. The gene is transcribed throughout development and translated into a polypeptide of ∼65 kDa. TPP1 activity was demonstrated for TPP1F-GFP immunoprecipitated from cells. Its activity could be inhibited by addition of the recombinant DUF3735 domain of GPHR. Knockout mutants did not display any particular phenotype, and TPP1 activity was not abrogated, presumably because compensates as it has the highest expression level of all the genes during growth. The GPHR interaction was not restricted to TPP1F but occurred also with TPP1B. As previous reports show that the majority of the TPP1 mutations in NCL resulted in reduction or loss of enzyme activity, we suggest that could be used as a model system in which to test new reagents that could affect the activity of the protein and ameliorate the disease.
三肽基肽酶1（TPP1）的突变与晚期婴儿神经元蜡样脂褐质沉积症（NCL）有关，NCL是一种神经退行性疾病。TPP1是一种溶酶体丝氨酸蛋白酶，可从蛋白质的N端去除三肽，由N端前结构域和催化结构域组成。它在哺乳动物、两栖动物、鱼类和变形虫中保守， 至少有六个编码TPP1的基因，从 到 。我们鉴定出TPP1F是高尔基体pH调节剂（GPHR）的结合伴侣，GPHR是一种在进化上高度保守的细胞内跨膜蛋白。包含GPHR的DUF3735（GPHR_N）结构域的区域负责这种相互作用。在TPP1F中，结合位点位于该蛋白的前结构域。 基因在整个发育过程中都有转录，并翻译成约65 kDa的多肽。从 细胞中免疫沉淀的TPP1F-GFP显示出TPP1活性。添加GPHR的重组DUF3735结构域可抑制其活性。敲除 突变体未显示任何特定表型，并且TPP1活性未被消除，推测是因为 在生长过程中所有 基因中表达水平最高，起到了补偿作用。GPHR的相互作用不仅限于TPP1F，也与TPP1B发生。正如先前的报道所示，NCL中大多数TPP1突变导致酶活性降低或丧失, 我们建议 可以用作测试可能影响该蛋白活性并改善疾病的新试剂的模型系统。
