Biomaterial Database

Identification of two KH domain proteins in the alpha-globin mRNP stability complex. 1995

M Kiledjian, and X Wang, and S A Liebhaber

Howard Hughes Medical Institute, Department of Genetics, Philadelphia 19104-6145, USA.

Accumulation of globin mRNAs during erythroid differentiation is dependent on their extraordinary stability. The longevity of human alpha-globin mRNA is associated with a ribonucleoprotein complex (alpha-complex) formed on the 3' untranslated region (3'UTR). One or more of the proteins within this alpha-complex contain strong polycytosine [poly(C)] binding (alpha PCB) activity. In the present report we purify alpha PCB activity from human erythroid K562 cells. Although not able to bind the alpha-globin 3'UTR directly, alpha PCB activity is sufficient to complement alpha-complex formation in a cytosolic extract depleted of poly(C) binding activity. Peptide microsequencing demonstrates that alpha PCB activity contains two structurally related poly(C) binding proteins. These two proteins, alpha-complex protein (alpha CP)-1 and -2, have an overall structural identity of 80% and contain three repeats of the K homology (KH) domain which is found in a subset of RNA binding proteins. Epitope-tagged recombinant alpha CP-1 and alpha CP-2 expressed in cells are each incorporated into the alpha-complex. We conclude that alpha CP-1 and alpha CP-2, members of the KH domain RNA binding protein family, are involved in formation of a sequence-specific alpha-globin mRNP complex associated with alpha-globin mRNA stability. As such this represents the first example of a specific function for this class of proteins and suggests potential roles for other members of this protein family.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D011066	Poly C	A group of cytosine ribonucleotides in which the phosphate residues of each cytosine ribonucleotide act as bridges in forming diester linkages between the ribose moieties.	Cytosine Polynucleotides,Polycytidylic Acid,Polycytidylic Acids,Acid, Polycytidylic,Acids, Polycytidylic,Polynucleotides, Cytosine
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D004915	Leukemia, Erythroblastic, Acute	A myeloproliferative disorder characterized by neoplastic proliferation of erythroblastic and myeloblastic elements with atypical erythroblasts and myeloblasts in the peripheral blood.	Di Guglielmo's Disease,Erythremic Myelosis,Erythroblastic Leukemia, Acute,Erythroleukemia,Leukemia, Myeloid, Acute, M6,Myeloid Leukemia, Acute, M6,Di Guglielmo Disease,Acute Erythroblastic Leukemia,Acute Erythroblastic Leukemias,Di Guglielmos Disease,Disease, Di Guglielmo,Disease, Di Guglielmo's,Erythremic Myeloses,Erythroblastic Leukemias, Acute,Erythroleukemias,Leukemia, Acute Erythroblastic,Leukemias, Acute Erythroblastic,Myeloses, Erythremic,Myelosis, Erythremic
D005914	Globins	A superfamily of proteins containing the globin fold which is composed of 6-8 alpha helices arranged in a characterstic HEME enclosing structure.	Globin
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D012261	Ribonucleoproteins	Complexes of RNA-binding proteins with ribonucleic acids (RNA).	Ribonucleoprotein