L10 ribosomal protein from Entamoeba histolytica share structural and functional homologies with QM/Jif-1: proteins with extraribosomal functions.
In the present work, the complete amino acid sequence of the Entamoeba histolytica ribosomal protein L10 (EhL10) is reported. cDNA of 630bp revealed an open reading frame that encodes a protein of 210 amino acids. Analysis of EhL10 ribosomal protein revealed 75% similarity and 57% identity with QM protein from Homo sapiens and 78 and 60%, respectively, with Arabidopsis thaliana. Western blot analysis of ribosomal proteins from E. histolytica showed that EhL10 protein is part of the ribosomal complex. Immunofluorescence analysis of EhL10 distribution in a transfected E. histolytica strain showed that EhL10 protein was mainly localized in the nucleus of trophozoites. Overexpression of EhL10 ribosomal protein in trophozoites transfected with the pExEhNeo/EhL10 vector exhibited a 60% reduction in cellular growth. DNA mobility-shift assays demonstrated that EhL10 ribosomal protein was able to destabilize the activating protein 1 (AP-1) complex binding specifically to the c-Jun-like protein. It is proposed in this study that the complex formation of EhL10 with c-Jun-like protein interferes with transcriptional activation of genes controlled by Jun (i.e. gene involved in cell growth). It is also being reported identification of a member of the AP-1 complex, the c-Jun-like protein, in nuclear extracts of E. histolytica using human-specific antibodies against this protein. The observations suggest that EhL10 may have an extraribosomal function in E. histolytica involved in suppression of cell proliferation in E. histolytica similar to the QM protein.
Chávez-Rios
Ramses
R
Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Apto. Postal 14-470, 07360, D.F., México, Mexico.
Arias-Romero
Luis Enrique
LE
Almaraz-Barrera
Ma de Jesús
Mde J
Hernández-Rivas
Rosaura
R
Guillén
Nancy
N
Vargas
Miguel
M
D000595:Amino Acid Sequence; D000818:Animals; D029681:Arabidopsis Proteins; D030161:Avian Proteins; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000502:physiology; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D004748:Entamoeba histolytica / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D015151:Immunoblotting / Q000379:methods; D008969:Molecular Sequence Data; D016755:Proto-Oncogene Proteins c-jun / Q000032:analysis / Q000276:immunology; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D000080882:Ribosomal Protein L10; D012269:Ribosomal Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D025521:Tumor Suppressor Proteins
D029681:Arabidopsis Proteins; D030161:Avian Proteins; D002352:Carrier Proteins; D016755:Proto-Oncogene Proteins c-jun; D015800:Protozoan Proteins; C000630686:RPL10 protein, human; D012269:Ribosomal Proteins; D025521:Tumor Suppressor Proteins; C082381:jif-1 protein, chicken; C000630691:ribosomal protein L10, Arabidopsis