LMP4 regulates Tbx5 protein subcellular localization and activity

Troy Camarata, Benjamin Bimber, Andre Kulisz, Teng Leong Chew, Jennifer Yeung, Hans Georg Simon*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


The limb- and heart-specific Tbx5 transcription factor coexpresses with and directly binds to the novel PDZ-LIM domain protein, LMP4. LMP4 is distributed in the cytoplasm associated with the actin cytoskeleton. In the presence of LMP4, Tbx5 shuttles dynamically between the nucleus and cytoplasm and, in a complex with LMP4, localizes to actin filaments. Nuclear and cytoplasmic Tbx5 distribution in developing chicken wings suggests the functional significance of the LMP4-Tbx5 interaction. In primary epicardial cells, we demonstrate that Tbx5 protein subcellular relocalization can be stimulated by external signals that induce cell differentiation. To test whether the relocalization from nuclear to cytoplasmic sites interferes with downstream gene expression, we used limb-specific Fgf10 and heart-specific Anf promoter-luciferase reporters and demonstrate that LMP4 acts as a repressor of Tbx5 activity. These studies reveal a previously unknown mechanism for Tbx transcription factor regulation in vertebrate limb and heart development and provide a better understanding of the molecular basis of hand/heart birth defects associated with Tbx5 mutations.

Original languageEnglish (US)
Pages (from-to)339-348
Number of pages10
JournalJournal of Cell Biology
Issue number3
StatePublished - Jul 31 2006

ASJC Scopus subject areas

  • Cell Biology


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