Characterization of functional urotensin II receptors in human skeletal muscle myoblasts: comparison with angiotensin II receptors

Peptides. 2005 Apr;26(4):683-90. doi: 10.1016/j.peptides.2004.11.018. Epub 2005 Jan 1.


The properties of urotensin II (U-II) receptor (UT receptor) and angiotensin II (ANG II) receptor (AT receptor) in primary human skeletal myoblasts (HSMM) and differentiated skeletal myotubes (HSMMT) were characterized. Radiolabeled U-II and ANG II bound specifically to HSMM with Kd's of 0.31 nM (2311 receptors/cell) and 0.61 nM (18,257 receptors/cell), respectively. The cyclic segment of U-II peptide, CFWKYC, was the minimal sequence required for binding, with the WKY residues essential. Inhibitor studies suggested AT1 is the predominant ANG II receptor. After radioligand binding, under conditions designed to minimize receptor internalization, half the bound U-II was resistant to acid washing suggesting that U-II binds tightly to its receptor in a quasi-irreversible fashion. The AT1 receptor-bound radioligand was completely removed under the same conditions. RT-PCR detected the expression of mRNAs for UT and AT1 receptors. Western blotting showed that U-II and ANG II signaled via ERK1/2 kinase. UT receptor was not lost upon differentiation into myotubes since both mRNA for UT receptor and U-II binding were still present. ANG II receptors were also present as shown by ANG II-induced calcium mobilization.

Publication types

  • Comparative Study

MeSH terms

  • Angiotensin II / pharmacology
  • Base Sequence
  • Calcium Signaling / drug effects
  • Calcium Signaling / physiology
  • Cell Culture Techniques
  • DNA Primers
  • Humans
  • Kinetics
  • Muscle, Skeletal / cytology
  • Muscle, Skeletal / physiology*
  • Myoblasts / cytology
  • Myoblasts / physiology*
  • Receptors, Angiotensin / genetics
  • Receptors, Angiotensin / physiology*
  • Receptors, G-Protein-Coupled / genetics
  • Receptors, G-Protein-Coupled / physiology*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Urotensins / metabolism


  • DNA Primers
  • Receptors, Angiotensin
  • Receptors, G-Protein-Coupled
  • UTS2R protein, human
  • Urotensins
  • Angiotensin II
  • urotensin II