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Myocardin Family Members Drive Formation of Caveolae.

Krawczyk KK, Yao Mattisson I, Ekman M, Oskolkov N, Grantinge R, Kotowska D, Olde B, Hansson O, Albinsson S, Miano JM, Rippe C, Swärd K - PLoS ONE (2015)

Bottom Line: The effect of LatB was associated with reduced mRNA levels for these genes and this was replicated by the MRTF inhibitor CCG-1423 which was non-additive with LatB.Knock down of the serum response factor (SRF), which mediates many of the effects of myocardin, decreased cavin-1 but increased caveolin-1 and -2 mRNAs.The myocardin family of transcriptional coactivators therefore drives formation of caveolae and this effect is largely independent of SRF.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Medical Science, BMC D12, Lund University, Lund, Sweden.

ABSTRACT
Caveolae are membrane organelles that play roles in glucose and lipid metabolism and in vascular function. Formation of caveolae requires caveolins and cavins. The make-up of caveolae and their density is considered to reflect cell-specific transcriptional control mechanisms for caveolins and cavins, but knowledge regarding regulation of caveolae genes is incomplete. Myocardin (MYOCD) and its relative MRTF-A (MKL1) are transcriptional coactivators that control genes which promote smooth muscle differentiation. MRTF-A communicates changes in actin polymerization to nuclear gene transcription. Here we tested if myocardin family proteins control biogenesis of caveolae via activation of caveolin and cavin transcription. Using human coronary artery smooth muscle cells we found that jasplakinolide and latrunculin B (LatB), substances that promote and inhibit actin polymerization, increased and decreased protein levels of caveolins and cavins, respectively. The effect of LatB was associated with reduced mRNA levels for these genes and this was replicated by the MRTF inhibitor CCG-1423 which was non-additive with LatB. Overexpression of myocardin and MRTF-A caused 5-10-fold induction of caveolins whereas cavin-1 and cavin-2 were induced 2-3-fold. PACSIN2 also increased, establishing positive regulation of caveolae genes from three families. Full regulation of CAV1 was retained in its proximal promoter. Knock down of the serum response factor (SRF), which mediates many of the effects of myocardin, decreased cavin-1 but increased caveolin-1 and -2 mRNAs. Viral transduction of myocardin increased the density of caveolae 5-fold in vitro. A decrease of CAV1 was observed concomitant with a decrease of the smooth muscle marker calponin in aortic aneurysms from mice (C57Bl/6) infused with angiotensin II. Human expression data disclosed correlations of MYOCD with CAV1 in a majority of human tissues and in the heart, correlation with MKL2 (MRTF-B) was observed. The myocardin family of transcriptional coactivators therefore drives formation of caveolae and this effect is largely independent of SRF.

No MeSH data available.


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Myocardin and MRTF-A transduction increases cavin mRNA levels.(A) Adenoviral transduction of hCASMC with MRTF-A (MKL1) elevates the mRNA expression of cavin-1, -2 and -3 (PTRF, SDPR and PRKCDBP respectively). (B) Adenoviral transduction with myocardin resulted in upregulation of cavin-1 and -2 but not of cavin-3 mRNA. (C) MRTF but not myocardin induced PACSIN2 mRNA expression. (D) mRNA expression for SRF, CNN1, CAV1, CAV2, PTRF and SDPR in cells transfected with negative control GAPmers (white bars) and with GAPmers targeting SRF (black bars). Data are presented as means±SEM. *P<0.05, **P<0.01, ***P<0.001.
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pone.0133931.g004: Myocardin and MRTF-A transduction increases cavin mRNA levels.(A) Adenoviral transduction of hCASMC with MRTF-A (MKL1) elevates the mRNA expression of cavin-1, -2 and -3 (PTRF, SDPR and PRKCDBP respectively). (B) Adenoviral transduction with myocardin resulted in upregulation of cavin-1 and -2 but not of cavin-3 mRNA. (C) MRTF but not myocardin induced PACSIN2 mRNA expression. (D) mRNA expression for SRF, CNN1, CAV1, CAV2, PTRF and SDPR in cells transfected with negative control GAPmers (white bars) and with GAPmers targeting SRF (black bars). Data are presented as means±SEM. *P<0.05, **P<0.01, ***P<0.001.

Mentions: The effect of MRTF-A and MYOCD transduction on cavin mRNA levels was next examined. Both MRTF-A (Fig 4A) and MYOCD (Fig 4B) induced PTRF and SDPR. MRTF-A had a small but significant effect on PRKCDBP, but MYOCD was without effect on this gene. We also tested whether MURC (cavin-4), which is enriched in striated muscles, was induced. If anything, MYOCD caused slight repression of MURC (data not shown). PACSIN2 which regulates membrane curvature in caveolae was induced by MRTF-A, but this gene was unaffected by myocardin (Fig 4C).


Myocardin Family Members Drive Formation of Caveolae.

Krawczyk KK, Yao Mattisson I, Ekman M, Oskolkov N, Grantinge R, Kotowska D, Olde B, Hansson O, Albinsson S, Miano JM, Rippe C, Swärd K - PLoS ONE (2015)

Myocardin and MRTF-A transduction increases cavin mRNA levels.(A) Adenoviral transduction of hCASMC with MRTF-A (MKL1) elevates the mRNA expression of cavin-1, -2 and -3 (PTRF, SDPR and PRKCDBP respectively). (B) Adenoviral transduction with myocardin resulted in upregulation of cavin-1 and -2 but not of cavin-3 mRNA. (C) MRTF but not myocardin induced PACSIN2 mRNA expression. (D) mRNA expression for SRF, CNN1, CAV1, CAV2, PTRF and SDPR in cells transfected with negative control GAPmers (white bars) and with GAPmers targeting SRF (black bars). Data are presented as means±SEM. *P<0.05, **P<0.01, ***P<0.001.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4526231&req=5

pone.0133931.g004: Myocardin and MRTF-A transduction increases cavin mRNA levels.(A) Adenoviral transduction of hCASMC with MRTF-A (MKL1) elevates the mRNA expression of cavin-1, -2 and -3 (PTRF, SDPR and PRKCDBP respectively). (B) Adenoviral transduction with myocardin resulted in upregulation of cavin-1 and -2 but not of cavin-3 mRNA. (C) MRTF but not myocardin induced PACSIN2 mRNA expression. (D) mRNA expression for SRF, CNN1, CAV1, CAV2, PTRF and SDPR in cells transfected with negative control GAPmers (white bars) and with GAPmers targeting SRF (black bars). Data are presented as means±SEM. *P<0.05, **P<0.01, ***P<0.001.
Mentions: The effect of MRTF-A and MYOCD transduction on cavin mRNA levels was next examined. Both MRTF-A (Fig 4A) and MYOCD (Fig 4B) induced PTRF and SDPR. MRTF-A had a small but significant effect on PRKCDBP, but MYOCD was without effect on this gene. We also tested whether MURC (cavin-4), which is enriched in striated muscles, was induced. If anything, MYOCD caused slight repression of MURC (data not shown). PACSIN2 which regulates membrane curvature in caveolae was induced by MRTF-A, but this gene was unaffected by myocardin (Fig 4C).

Bottom Line: The effect of LatB was associated with reduced mRNA levels for these genes and this was replicated by the MRTF inhibitor CCG-1423 which was non-additive with LatB.Knock down of the serum response factor (SRF), which mediates many of the effects of myocardin, decreased cavin-1 but increased caveolin-1 and -2 mRNAs.The myocardin family of transcriptional coactivators therefore drives formation of caveolae and this effect is largely independent of SRF.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Medical Science, BMC D12, Lund University, Lund, Sweden.

ABSTRACT
Caveolae are membrane organelles that play roles in glucose and lipid metabolism and in vascular function. Formation of caveolae requires caveolins and cavins. The make-up of caveolae and their density is considered to reflect cell-specific transcriptional control mechanisms for caveolins and cavins, but knowledge regarding regulation of caveolae genes is incomplete. Myocardin (MYOCD) and its relative MRTF-A (MKL1) are transcriptional coactivators that control genes which promote smooth muscle differentiation. MRTF-A communicates changes in actin polymerization to nuclear gene transcription. Here we tested if myocardin family proteins control biogenesis of caveolae via activation of caveolin and cavin transcription. Using human coronary artery smooth muscle cells we found that jasplakinolide and latrunculin B (LatB), substances that promote and inhibit actin polymerization, increased and decreased protein levels of caveolins and cavins, respectively. The effect of LatB was associated with reduced mRNA levels for these genes and this was replicated by the MRTF inhibitor CCG-1423 which was non-additive with LatB. Overexpression of myocardin and MRTF-A caused 5-10-fold induction of caveolins whereas cavin-1 and cavin-2 were induced 2-3-fold. PACSIN2 also increased, establishing positive regulation of caveolae genes from three families. Full regulation of CAV1 was retained in its proximal promoter. Knock down of the serum response factor (SRF), which mediates many of the effects of myocardin, decreased cavin-1 but increased caveolin-1 and -2 mRNAs. Viral transduction of myocardin increased the density of caveolae 5-fold in vitro. A decrease of CAV1 was observed concomitant with a decrease of the smooth muscle marker calponin in aortic aneurysms from mice (C57Bl/6) infused with angiotensin II. Human expression data disclosed correlations of MYOCD with CAV1 in a majority of human tissues and in the heart, correlation with MKL2 (MRTF-B) was observed. The myocardin family of transcriptional coactivators therefore drives formation of caveolae and this effect is largely independent of SRF.

No MeSH data available.


Related in: MedlinePlus