Hic-5 is required for fetal gene expression and cytoskeletal organization of neonatal cardiac myocytes

Erin E. Yund, Joseph A Hill, Rebecca S. Keller

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Cardiac costameres link the extracellular matrix to the sarcomere at the z-disc and contain proteins such as integrins and other signaling molecules implicated in the regulation of pathological hypertrophy. Paxillin family members, hic-5 and paxillin, are scaffolding proteins associated with the integrin complex that have been shown to mediate numerous protein interactions in other cell types. While paxillin has been described in postnatal heart, hic-5 has not been identified. Our results provide evidence of hic-5 in neonatal cardiac myocytes co-localized with paxillin and α-actinin at the z-discs and the ends of actin filaments. Treatment with the hypertrophic agonist phenylephrine resulted in increased hic-5 expression while having no effect on paxillin levels. To see if increased hic-5 expression was sufficient to induce changes in cytoskeletal organization, hic-5 was overexpressed in myocytes by adenoviral infection. Hic-5 overexpression significantly increased the number of cells with organized cytoskeleton. Using siRNA mediated knockdown, we examined the requirement of hic-5 and paxillin in regulation of phenylephrine induced gene expression and cytoskeletal organization. Our results indicate that hic-5, not paxillin is required for upregulation of ANF and α-skeletal actin genes as well as in cytoskeletal reorganization. Finally, we demonstrated that hic-5 upregulation occurs downstream of MEK1/2-ERK1/2 signaling as inhibition of MEK1/2 using U0126 inhibitor completely inhibited hic-5 upregulation by PE. In a complimentary study, we showed that hic-5 knockdown had no effect on PE induced ERK1/2 phosphorylation. These findings demonstrate a novel role for hic-5 in the regulation of actin cytoskeleton and fetal gene expression.

Original languageEnglish (US)
Pages (from-to)520-527
Number of pages8
JournalJournal of Molecular and Cellular Cardiology
Volume47
Issue number4
DOIs
StatePublished - Oct 2009

Fingerprint

Paxillin
Cardiac Myocytes
Gene Expression
Up-Regulation
Phenylephrine
Actin Cytoskeleton
Integrins
Costameres
Actinin
Sarcomeres
Proteins
Atrial Natriuretic Factor
Cytoskeleton
Muscle Cells
Hypertrophy
Small Interfering RNA
Extracellular Matrix
Actins
Cell Count
Phosphorylation

Keywords

  • Cytoskeleton
  • Fetal gene
  • Hic-5
  • Hypertrophy
  • Paxillin

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

Cite this

Hic-5 is required for fetal gene expression and cytoskeletal organization of neonatal cardiac myocytes. / Yund, Erin E.; Hill, Joseph A; Keller, Rebecca S.

In: Journal of Molecular and Cellular Cardiology, Vol. 47, No. 4, 10.2009, p. 520-527.

Research output: Contribution to journalArticle

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