Transduction of the N-Terminal Fragments of MYPT1 Enhances Myofilament Ca2+ Sensitivity in an Intact Coronary Artery

Katsuya Hirano, Dmitry N. Derkach, Mayumi Hirano, Junji Nishimura, Shosuke Takahashi, Hideo Kanaide

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Objective - The region of the 110 kDa regulatory subunit (MYPT1) of smooth muscle myosin phosphatase involved in the regulation of contraction was determined under physiological conditions. Methods and Results - Using HIV Tat protein-mediated protein transduction, the N-terminal fragments of MYPT1 were introduced to the intact porcine coronary arterial strips. Pre-incubation with 3 μmol/L TAT-MYPT11-374, a construct containing the Tat peptide and the residues 1 to 374 of MYPT1, for 15 minutes augmented (2.4-fold) the subsequent contraction induced by adding 1.25 mmol/L of extracellular Ca 2+ under 118 mmol/L K+ depolarization, with no augmentation of the [Ca2+]i elevation. The deletion of the Tat peptide, MYPT11-374, abolished the augmenting effect. TAT-MYPT11-296 demonstrated a weaker but significant augmentation (1.7-fold). However, TAT-MYPT11-171, TAT-MYPT139-374, TAT-MYPT139-296, and TAT-MYPT1297-374 had no augmenting activity. The myosin light chain phosphorylation level as a function of extracellular Ca2+ concentrations was shifted to the left in the strips pretreated with TAT-MYPT11-374 compared with the control. Conclusions - Region 1 to 296 was the minimal region involved in the enhancement of contraction, and region 297 to 374 played a supplemental role. These results suggested that the interaction mainly between catalytic subunit and MYPT1 play a critical role in the regulation of the endogenous myosin phosphatase in intact smooth muscle.

Original languageEnglish
Pages (from-to)464-469
Number of pages6
JournalArteriosclerosis, thrombosis, and vascular biology
Volume24
Issue number3
DOIs
Publication statusPublished - Mar 1 2004

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Myosin-Light-Chain Phosphatase
Myofibrils
Coronary Vessels
Human Immunodeficiency Virus tat Gene Products
Smooth Muscle Myosins
Myosin Light Chains
Peptides
Smooth Muscle
Catalytic Domain
Swine
Phosphorylation
Proteins

All Science Journal Classification (ASJC) codes

  • Cardiology and Cardiovascular Medicine

Cite this

Transduction of the N-Terminal Fragments of MYPT1 Enhances Myofilament Ca2+ Sensitivity in an Intact Coronary Artery. / Hirano, Katsuya; Derkach, Dmitry N.; Hirano, Mayumi; Nishimura, Junji; Takahashi, Shosuke; Kanaide, Hideo.

In: Arteriosclerosis, thrombosis, and vascular biology, Vol. 24, No. 3, 01.03.2004, p. 464-469.

Research output: Contribution to journalArticle

Hirano, Katsuya ; Derkach, Dmitry N. ; Hirano, Mayumi ; Nishimura, Junji ; Takahashi, Shosuke ; Kanaide, Hideo. / Transduction of the N-Terminal Fragments of MYPT1 Enhances Myofilament Ca2+ Sensitivity in an Intact Coronary Artery. In: Arteriosclerosis, thrombosis, and vascular biology. 2004 ; Vol. 24, No. 3. pp. 464-469.
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