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Light-mediated Reversible Modulation of the Mitogen-activated Protein Kinase Pathway during Cell Differentiation and Xenopus Embryonic Development
09:32

Light-mediated Reversible Modulation of the Mitogen-activated Protein Kinase Pathway during Cell Differentiation and Xenopus Embryonic Development

Published on: June 15, 2017

Role for p21-activated kinase PAK4 in development of the mammalian heart

Tanya Nekrasova1, Audrey Minden

  • 1Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 164 Frelinghuysen Road, Piscataway, NJ 08854, USA.

Transgenic Research
|December 17, 2011
PubMed

Insights

The serine-threonine kinase PAK4 is essential for heart development. Its absence causes severe cardiac deficits, impacting outflow tract formation and cardiomyocyte function, leading to embryonic lethality.

Area of Science:

  • Cardiovascular biology
  • Developmental biology
  • Molecular cell biology

Background:

  • The serine-threonine kinase PAK4 is crucial for cell proliferation, survival, and cytoskeletal regulation.
  • Pak4 knockout mice exhibit embryonic lethality before embryonic day 11.
  • PAK4 is highly expressed in embryonic hearts, decreasing in adults.

Purpose of the Study:

  • To investigate the role of PAK4 in heart development using knockout mouse models.
  • To elucidate the specific cardiac defects arising from Pak4 deficiency.

Main Methods:

  • Generation and analysis of conventional and conditional Pak4 knockout mice and embryos.
  • Assessment of cardiac morphology and function at various developmental stages.
  • Depletion of PAK4 in cultured cardiomyocytes to study cellular effects.

Main Results:

  • Pak4 deficiency severely impacts cardiogenesis from early stages, with profound heart deficits by embryonic day 9.5.
  • Conditional Pak4 deletion in the secondary heart field progenitors results in outflow tract abnormalities, including a narrower pulmonary artery and thinner aortic wall.
  • Conditional knockouts show enlarged right ventricles and atria, reduced LIMK1 levels, compromised sarcomeric structure, and impaired contraction in cardiomyocytes.

Conclusions:

  • PAK4 is indispensable for normal heart development, regulating actin dynamics and cytoskeletal organization.
  • Loss of PAK4 function leads to specific cardiac malformations and functional deficits, explaining embryonic lethality.

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