The human gene AHNAK encodes a large phosphoprotein located primarily in the nucleus.
AHNAK is a newly identified human gene notable for the exceptional size (c.a. 700 kD) and structure of its product, and for the repression of its expression in human neuroblastoma cells. Here we report the identification and partial characterization of the protein encoded by AHNAK. The protein is located principally (but not exclusively) in the nucleus and is phosphorylated on both serine and threonine. The abundance of the protein increases appreciably when cells withdraw from the division cycle, in response to either withdrawal of serum (fibroblasts) or differentiation (neuroblastoma cells). By contrast, the amount of phosphorylation appears to diminish in those settings. The considerable abundance and conjectured fibrous structure of AHNAK protein suggest a role in cytoarchitecture, but no function can yet be discerned.
Department of Microbiology and Immunology, University of California, San Francisco 94143.
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Shtivelman
J M
JM
Bishop
D000595:Amino Acid Sequence; D015153:Blotting, Western; D018288:Carcinoma, Small Cell; D002454:Cell Differentiation / Q000187:drug effects; D002458:Cell Fractionation; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure*; D005455:Fluorescent Antibody Technique; D006801:Humans; D007106:Immune Sera; D008175:Lung Neoplasms; D008545:Melanoma; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D009447:Neuroblastoma; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology; D010750:Phosphoproteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
C075176:AHNAK protein, human; D007106:Immune Sera; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D010455:Peptides; D010750:Phosphoproteins; D014212:Tretinoin