Screening And Identifying Of LOH12CR1: A Novel Interactive Protein Of STK11

Objective:Peutz-Jeghers(PJ)syndrome is an autosomal-dominant disorder characterized by melanocytic macules of the lips,multiple gastrointestinal hamartomatous polyps and an increased risk for various neoplasms,including gastrointestinal cancer. The incidence frequency of PJS is varied greatly from 1/10000 to 1/12000.Recently the disease gene STK11 was mapped to chromosome 19p13.3,extending over 23 kb of genomic DNA and composed of 9 exons,encoding the serine/threonine kinase which is consisited of 433 amino acid residues and highly conserved in the evolution process.It can regulate cell cycle,cell polarity and cell basic energy metabolism.Although the mutation in STK11 catalytic domain is responsible for the loss of its function,many mutations in the C-terminal region of STK11 have been identified in PJS as well as in other tumors.Since the C-terminal including 123 amino acid residue has multiple post-translational modification locus,it maybe play an important role in tumorigeness,but the mechanism is unclear.Methods:In order to further investigate the function of the C-terminal of STK11,we cloned and inserted it into the prokaryotic expression system of pGEX4T-2,and induced the expression of the fusion protein GST-STK11,then purified the highly soluble fusion protein with the Glutathione Sepharose,then we screened the LOH12CR1 which can be interacted with the C-terminal region of STK11 by GST-pull down and mass chromatographic analysis. LOH12CR1,located on the 12p,is the candidate gene of suppressor tumor gene and highly reserved in evolution.Results:The LOH12CR1 can co-localize with STK11 by immunofluorescence test,also we proved that they can interact by co-immunoprecipitation,however they do not directly affect in mammalian two-hybrid assay system.Conclusion:Our research found the novel interaction protein LOH12CR1 of STK11,therefore provided a new clue for the research of its function.