Rat vas deferens SERCA2 is modulated by Ca2+/calmodulin protein kinase II-mediated phosphorylation.
Braz J Med Biol Res
; 46(3): 227-34, 2013 03.
Article
em En
| MEDLINE
| ID: mdl-23558856
ABSTRACT
Ca2+ pumps are important players in smooth muscle contraction. Nevertheless, little information is available about these pumps in the vas deferens. We have determined which subtype of sarco(endo)plasmic reticulum Ca2+-ATPase isoform (SERCA) is expressed in rat vas deferens (RVD) and its modulation by calmodulin (CaM)-dependent mechanisms. The thapsigargin-sensitive Ca2+-ATPase from a membrane fraction containing the highest SERCA levels in the RVD homogenate has the same molecular mass (â¼115â
kDa) as that of SERCA2 from the rat cerebellum. It has a very high affinity for Ca2+ (Ca0.5 = 780â
nM) and a low sensitivity to vanadate (IC50 = 41â
µM). These facts indicate that SERCA2 is present in the RVD. Immunoblotting for CaM and Ca2+/calmodulin-dependent protein kinase II (CaMKII) showed the expression of these two regulatory proteins. Ca2+ and CaM increased serine-phosphorylated residues of the 115-kDa protein, indicating the involvement of CaMKII in the regulatory phosphorylation of SERCA2. Phosphorylation is accompanied by an 8-fold increase of thapsigargin-sensitive Ca2+ accumulation in the lumen of vesicles derived from these membranes. These data establish that SERCA2 in the RVD is modulated by Ca2+ and CaM, possibly via CaMKII, in a process that results in stimulation of Ca2+ pumping activity.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ducto Deferente
/
Proteínas de Ligação ao Cálcio
/
Calmodulina
/
Proteínas Serina-Treonina Quinases
/
ATPases Transportadoras de Cálcio
Limite:
Animals
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article