Annexin II up-regulates cellular levels of p11 protein by a post-translational mechanisms.
Annexin II (p36) and p11, which belong to two different families of calcium-binding proteins, are able to form a heterotetrameric protein complex (p36)2(p11)2 called calpactin I. As these proteins were detectable only in the presence of each other in a variety of cell lines, we studied the mechanisms of regulation of cellular levels of annexin II and p11. In cells expressing p11 messenger RNA, p11 protein is undetectable unless annexin II is also expressed. As an example, the hepatoblastoma HepG2 cell line displays no detectable annexin II nor p11 protein, although it expresses p11 mRNA. The overexpression of annexin II by gene transfer into HepG2 cells leads to the up-regulation of the cellular levels of p11 by a post-translational mechanism. In the presence of annexin II, there is no major change in the p11 transcript levels, but the half-life of the p11 protein is increased more than 6-fold. Thus, the degree of expression of annexin II, which varies according to different states of cellular differentiation and transformation, is an essential factor in the regulation of cellular levels of p11.
Laboratoire d'Oncologie Moléculaire, INSERM CJF 9302, Centre León Bérard, Lyon, France.
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Puisieux
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Ji
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Ozturk
D017306:Annexin A2 / Q000378:metabolism*; D001483:Base Sequence; D015152:Blotting, Northern; D006528:Carcinoma, Hepatocellular / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000378:metabolism; D009418:S100 Proteins; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000502:physiology*; D000099248:S100 Calcium Binding Protein A10
D017306:Annexin A2; D010455:Peptides; D012333:RNA, Messenger; D009418:S100 Proteins; D000099248:S100 Calcium Binding Protein A10