The Study Of GOLPH2Structure And Function

Golgi phosphoprotein2(GOLPH2) is a type II Golgi resident membrane protein and up-regulated in kinds of cancers and liver diseases. Although GOLPH2has been identified as a serum biomarker of hepatocellular cancer, no structural information has yet been reported and the function of GOLPH2hasn’t been elucidated.In this study, we aimed to explore the function of GOLPH2with two different strategies:(1) Identify the interaction protein of GOLPH2;(2) Study the function of golph2during early development of Xenopus laevis.We found GOLPH2interacted with itself. The results indicate that intercellular GOLPH2and secreted GOLPH2exist as a disulfide-bonded dimer. The coiled-coil region independent of two intermolecular disulfide bonds was sufficient for their dimerization using co-immunoprecipitation and a yeast two-hybrid approach. These results can help in understanding the structure-function relationship of GOLPH2. Using GOLPH2as bait, yeast two-hybrid was performed to screen against a human liver cDNA library, and angiotensinogen (AGT) was identified as a putative interaction partner of GOLPH2. Using co-immunoprecipitation assays, we showed that GOLPH2interacted with AGT. We also showed that GOLPH2interacted and co-localized with CASC4in the Golgi complexGOLPH2is a highly conserved protein. The Xenopus model is used to study the function of human proteins. We describe the isolation and characterization of Xenopus golph2, which dimerizes and localizes to the Golgi in a manner similar to human GOLPH2. Xenopus golph2is expressed in the pronephros during early development. The morpholino-mediated knockdown of golph2results in edema formation. Additionally, Nephrin expression is enhanced in the glomus, and the expression of pronephric marker genes, such as atplbl, C1C-K, NKCC2, and NBC1, is diminished in the tubules and duct. Expression patterns of the transcription factors WT1, Pax2, Pax8, Liml, GATA3, and HNF1β are examined in the embryos lacking endogenous golph2, the expression of WT1is increased in the glomus and expanded laterally in the pronephric region. We conclude that the deletion of golph2causes an increase in the expression of WT1, which may promote glomus formation and inhibit pronephric tubule differentiation.