title: [Analysis on the relationship between p57 and cholesterol in cellular membrane].
abstract: OBJECTIVE
  To investigate the relationship between p57 and cholesterol in cellular membrane under physiological conditions.
  
  
  METHODS
  Different concentrations of mbetaCD were used to extract cholesterol from cellular membrane of U937 cells. The cellular membrane was prepared by ultracentrifugation and the content change of p57 in cellular membrane component was measured by Western blot analysis. Discontinuous sucrose density gradient centrifugation was used to prepare lipid rafts and the content of p57 in them was measured by Western blot analysis.
  
  
  RESULTS
  The degradation of cholesterol level in cellular membrane didn't lead to obvious content change of p57 in cellular membrane component. Furthermore, no p57 protein was found in lipid rafts.
  
  
  CONCLUSIONS
  No relationship between p57 and cholesterol in cellular membrane was found in the physiological condition, which is obviously different from that in pathological condition caused by the invasion of pathogenic mycobacteria.
authors.affiliation: Department of Endocrinology, Peking University First Hospital, Beijing 100034, China.
authors.forename: Meng-meng
authors.initials: MM
authors.lastname: Jin
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Hung
authors.forename: Shi-qian
authors.initials: SQ
authors.lastname: Zhang
authors.forename: Li-cheng
authors.initials: LC
authors.lastname: Zhang
authors.forename: Pei-fu
authors.initials: PF
authors.lastname: Tang
mesh_terms: D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D002784:Cholesterol / Q000032:analysis / Q000378:metabolism*; D050761:Cyclin-Dependent Kinase Inhibitor p57 / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D020298:U937 Cells
chemical_list: C493964:CDKN1C protein, human; D050761:Cyclin-Dependent Kinase Inhibitor p57; D002784:Cholesterol