Retraction of: Acetylation of GATA4 on Lysine Residue K313 Promotes Osteoblastic Cells Growth

Background/Aims: GATA4, a protein related to osteoblast differentiation and mineralization, whose acetylation is essential for cardiac defects. Here, we aimed to explore the functional impacts of GATA4 acetylation on osteoporosis (OS). Methods: GATA4 acetylation in hFOB1.19 and 293T cells was detected after exposure of HDAC inhibitors (TSA and SAHA). Co-immunoprecipitation was conducted to determine which HATs and HDACs was involved in the modulation of GATA4 acetylation/deacetylation, and to identify the acetylation site. The transcriptional activity of GATA4 was measured in the presence or absence of cycloheximide. Furthermore, hFOB1.19 cells viability and apoptosis were evaluated after transfection with acetylation-defective mutant of GATA4. Results: As a result, GATA4 acetylation was identified as a pivotal event in hFOB1.19 cells. GATA4 can be acetylated by P300/CBP, and the acetylation site was on lysine residue K313. Besides, the acetylation of GATA4 can be impaired by HDAC1, rather than by HDAC2-5. GATA4 acetylation contributed to the stability and transcription of GATA4. Moreover, GATA4 acetylation activated CCND2 transcription, and mutation of GATA4 on K-313 reduced cell viability and increased a mitochondria-dependent apoptosis in hFOB1.19 cells. Conclusion: Our data suggest that GATA4 exists as an acetylated protein in hFOB1.19 cells. Acetylation regulates the stability and transcription of GATA4, and activates CCND2 transcription, which may explain the growth-promoting functions of GATA4 in hFOB1.19 cells.

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The Action of Thrombin on Modified Fibrinogen

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657364 ◽

1983 ◽

Vol 49 (03) ◽

pp. 208-213

Author(s):

A J Osbahr

Keyword(s):

Physical Properties ◽

Negative Charge ◽

Lysine Residue ◽

Fibrinopeptide A ◽

Amino Groups ◽

Lysine Residues ◽

Citraconic Anhydride

SummaryThe modification of canine fibrinogen with citraconic anhydride modified the ε-amino groups of the fibrinogen and at the same time generated additional negative charges into the protein. The addition of thrombin to the modified fibrinogen did not induce polymerization; however, the fibrinopeptide was released at a faster rate than from the unmodified fibrinogen. The physical properties of the citraconylated fibrinogen were markedly altered by the modification of 50-60 lysine residues in one hour. A modified fibrinopeptide-A was released by thrombin from the modified fibrinogen and was electrophoretically more anionic than the unmodified fibrinopeptide-A. Edman analysis confirmed the modification of the lysine residue present in the peptide. The rate of removal of citraconylated fibrinopeptide-A from modified fibrinogen by thrombin was 30 to 40 percent greater than the cleavage of unmodified fibrinopeptide-A from unmodified fibrinogen. However, the modification of 60 or more lysine residues in the fibrinogen produced a decrease in the rate of cleavage of citraconylated fibrinopeptide-A. The results suggest that additional negative charge in the vicinity of the attachment of fibrinopeptide-A to canine fibrinogen aids in the removal of the peptide by thrombin.

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