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Human heart LIM protein has transcription activation ability related to LIM domain 1

Bin Zheng1, Mei Han, Jin-Kun Wen

  • 1Department of Biochemistry, Hebei Medical University, Shijiazhuang, China.

Biochemistry. Biokhimiia
|April 9, 2008
PubMed

Insights

Human heart LIM (hhLIM), a cardiac hypertrophy gene coactivator, activates ANF gene transcription. Its N-terminal LIM domain 1 is crucial for this function, highlighting hhLIM's role in cardiac gene regulation.

Area of Science:

  • Molecular Biology
  • Cardiovascular Research

Background:

  • Cardiac hypertrophy involves complex gene regulation.
  • Transcriptional coactivators play a key role in this process.
  • The human heart LIM (hhLIM) protein is a muscle-specific coactivator.

Purpose of the Study:

  • To investigate the role of hhLIM in regulating cardiac hypertrophy-related genes.
  • To identify the specific domains of hhLIM responsible for transcriptional activation.
  • To understand the mechanism of hhLIM's function in cardiac gene expression.

Main Methods:

  • Utilized H9C2 cells, a cardiac myoblast cell line.
  • Performed gene promoter activity assays (e.g., ANF gene promoter).
  • Employed site-directed mutagenesis to study protein domains and phosphorylation sites.

Main Results:

  • hhLIM significantly stimulates ANF gene promoter activity in H9C2 cells.
  • The N-terminal half of hhLIM is essential for this transcriptional activation.
  • LIM domain 1 and its conserved cysteine residues are critical for hhLIM's function.
  • Protein kinase C phosphorylation site is also important for activation.

Conclusions:

  • hhLIM acts as a potent transcriptional coactivator for cardiac hypertrophy genes.
  • LIM domain 1 is a key functional domain in hhLIM's transcriptional activity.
  • hhLIM represents a typical member of the LIM family with significant roles in cardiac gene regulation.

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