PMID- 12416717
OWN - NLM
STAT- MEDLINE
DCOM- 20030409
LR  - 20220716
IS  - 0142-4319 (Print)
IS  - 0142-4319 (Linking)
VI  - 23
IP  - 2
DP  - 2002
TI  - Characterization of specific GTP binding sites in C2C12 mouse skeletal muscle 
      cells.
PG  - 107-18
AB  - Receptor sites, specific for guanosine 5'-triphosphate (GTP) were characterised 
      in myoblasts and myotubes of C2C12 mouse skeletal muscle cells, using binding 
      experiments and measurements of intracellular Ca2+ concentration ([Ca2+]i). We 
      identified two GTP binding sites in myoblasts membranes: a high affinity site (Kd 
      = 15.4 +/- 4.6 microM; Bmax = 1.7 +/- 0.5 nmol mg(-1) protein); and a low 
      affinity site (Kd = 170 +/- 94.5 microM; Bmax = 14.2 +/- 3.9 nmol mg(-1) 
      protein). In myotube membranes only a low affinity binding site for GTP (Kd = 169 
      +/- 39 microM; Bmax = 12.3 +/- 1.4 nmol mg(-1) protein) was detected. In 
      myoblasts GTP binding was not displaced by ATP or UTP, even at high 
      concentrations (up to of 1 mM), but it was affected by treatments with suramin or 
      Reactive Blue 2 (RB2), the non-selective purine receptor antagonists. In 
      contrast, in myotubes GTP binding was partially displaced by high concentrations 
      of ATP, but treatments with the non-selective purine receptor antagonists, 
      suramin or RB2, and with UTP had no effect on GTP binding. The addition of GTP to 
      myoblasts, and to myotubes, resulted in elevations of [Ca2+]i. The patterns of 
      Ca2+ response however, were different in the two cell phenotypes. In myoblasts 
      the addition of GTP induced two types of Ca2+ responses: (1) a fast increase in 
      [Ca2+]i, followed by a sustained [Ca2+]i elevation, and (2) a slow raising and 
      steady prolonged increase in [Ca2+]i. In myotubes, however only fast Ca2+ 
      responses were observed following the addition of 500 microM GTP. In the 
      myoblasts and myotubes GTP-stimulated [Ca2+]i increases were abolished by 
      treatments with suramin or RB2 at concentrations which had no effect on the 
      ATP-induced Ca2+ responses. We conclude, that C2C12 cells express two distinct 
      binding sites for GTP before differentiation, but only one after, the low 
      affinity binding site. These results suggest a possible role of the high affinity 
      GTP binding site in early stage of development of skeletal muscle.
FAU - Pietrangelo, Tiziana
AU  - Pietrangelo T
AD  - Dipartimento di Scienze del Farmaco, Universita G. d'Annunzio, Chieti, Italy.
FAU - Mariggio, Maria A
AU  - Mariggio MA
FAU - Lorenzon, Paola
AU  - Lorenzon P
FAU - Fulle, Stefania
AU  - Fulle S
FAU - Protasi, Feliciano
AU  - Protasi F
FAU - Rathbone, Michel
AU  - Rathbone M
FAU - Werstiuk, Eva
AU  - Werstiuk E
FAU - Fano, Giorgio
AU  - Fano G
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Netherlands
TA  - J Muscle Res Cell Motil
JT  - Journal of muscle research and cell motility
JID - 8006298
RN  - 86-01-1 (Guanosine Triphosphate)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Animals
MH  - Binding Sites/drug effects
MH  - Calcium/metabolism
MH  - Cell Line
MH  - Guanosine Triphosphate/*metabolism/pharmacology
MH  - Mice
MH  - Muscle, Skeletal/drug effects/*metabolism
MH  - Myoblasts, Skeletal/drug effects/*metabolism
EDAT- 2002/11/06 04:00
MHDA- 2003/04/10 05:00
CRDT- 2002/11/06 04:00
PHST- 2002/11/06 04:00 [pubmed]
PHST- 2003/04/10 05:00 [medline]
PHST- 2002/11/06 04:00 [entrez]
AID - 10.1023/a:1020288117082 [doi]
PST - ppublish
SO  - J Muscle Res Cell Motil. 2002;23(2):107-18. doi: 10.1023/a:1020288117082.