Screening Interactive Protein Of LOH12CR1 By Yeast Two-Hybrid

Peutz-Jeghers Syndrome is an autosomal dominantly inherited disease characterized by melanocytic macules on the lips, perioral and buccal regions and by multiple gastrointestinal polyps most of which are hamartomatous type. Furthermore, this syndrome is associated with benign and malignant neoplasms of the intestinal tract, the pancreas, ovaries, etc. The syndrome is caused by mutations in a gene named STK11 (also known as LKB1) that has been shown to encode a widely expressed serine/threonine kinase. Thus far, physiological substrates have been identified of this enzyme, Overexpression of STK11/LKB1 in cells leads to a G1-cell cycle arrest, indicating that STK11/LKB1 may function as a tumour suppressor.The present research has confirmed the main physiological functions of STK11/LKB1:involved in maintaining cell polarity, arrests cell cycle, promotes cell apoptosis, regulates cell energy metabolism and the development of embryo, regulates signal transduction, inhibits tumor cell proliferation. The Understanding of functions of STK11/LKB1 is largely due to the discoveries of its interactive proteins. By interacting with these proteins, STK11/LKB1 may participate the physiological processes of cell through multiple paths. LOH12CR1 is a new interactive protein of STK11/LKB1 that our group has screened and defined by using the method of GST-Pull down with mass chromatographic analysis and co-immunoprecipitation. This protein is located in the short arm of chromosome 12. In the hematopoietic system, ovarian, breast and lung cancer, there is often efferency of heterozygote in the region of LOH12CR1. Previous study has confirmed that LOH12CR1 widely expressed in many organizations. The human LOH12CRI and the mice, nematodes, and drosophila LOH12CRI hypothetical proteins are highly homologous, suggest that it is a protein of important functions. There is also a certain homology in LOH12CR1, spectrin repeats region of guanine nucleotide exchange factor TRIO and some region of Mekk4 protein. LOH12CRI scatteres in the cytoplasm showing coarse speckled under the laser confocal microscopy. Only a few locates in the nucleus. Furthermore, overexpression of LOH12CRI can inhibit cell growth and proliferation effectively. This function is not dependent on the endogenous expression of STK11/LKB1. To confirm that whether there is a synergistic effect of the mechanism of STK11/LKB1 and LOH12CR1, and whether there is a need of auxiliary proteins for interaction between the two proteins. We use the MatchmakerTM Gold Yeast Two-Hybrid System and screen the interactive proteins of LOH12CR1, the results may shed light on the interactive mechanisms of STK11/LKB1 with LOH12CR1.