TY - JOUR
T1 - Differential Effects of G- and F-Actin on the Plasma Membrane Calcium Pump Activity
AU - Vanagas, Laura
AU - de La Fuente, María Candelaria
AU - Dalghi, Marianela
AU - Ferreira-Gomes, Mariela
AU - Rossi, Rolando C.
AU - Strehler, Emanuel E.
AU - Mangialavori, Irene C.
AU - Rossi, Juan P.F.C.
N1 - Funding Information:
Acknowledgments The present work was supported by the NIH, Fogarty International Center Grant R03TW006837 to JPFCR and by ANPCYT, CONICET and UBACYT from Argentina. MCDLF, LV, MD, and MFG are doctoral fellows of CONICET. ICM, RCR and JPFCR are established investigators of CONICET, Argentina. EES is an established researcher of Mayo/Clinic Foundation, Rochester, MN, USA.
PY - 2013/5
Y1 - 2013/5
N2 - We have previously shown that plasma membrane calcium ATPase (PMCA) pump activity is affected by the membrane protein concentration (Vanagas et al., Biochim Biophys Acta 1768:1641-1644, 2007). The results of this study provided evidence for the involvement of the actin cytoskeleton. In this study, we explored the relationship between the polymerization state of actin and its effects on purified PMCA activity. Our results show that PMCA associates with the actin cytoskeleton and this interaction causes a modulation of the catalytic activity involving the phosphorylated intermediate of the pump. The state of actin polymerization determines whether it acts as an activator or an inhibitor of the pump: G-actin and/or short oligomers activate the pump, while F-actin inhibits it. The effects of actin on PMCA are the consequence of direct interaction as demonstrated by immunoblotting and cosedimentation experiments. Taken together, these findings suggest that interactions with actin play a dynamic role in the regulation of PMCA-mediated Ca2+ extrusion through the membrane. Our results provide further evidence of the activation-inhibition phenomenon as a property of many cytoskeleton-associated membrane proteins where the cytoskeleton is no longer restricted to a mechanical function but is dynamically involved in modulating the activity of integral proteins with which it interacts.
AB - We have previously shown that plasma membrane calcium ATPase (PMCA) pump activity is affected by the membrane protein concentration (Vanagas et al., Biochim Biophys Acta 1768:1641-1644, 2007). The results of this study provided evidence for the involvement of the actin cytoskeleton. In this study, we explored the relationship between the polymerization state of actin and its effects on purified PMCA activity. Our results show that PMCA associates with the actin cytoskeleton and this interaction causes a modulation of the catalytic activity involving the phosphorylated intermediate of the pump. The state of actin polymerization determines whether it acts as an activator or an inhibitor of the pump: G-actin and/or short oligomers activate the pump, while F-actin inhibits it. The effects of actin on PMCA are the consequence of direct interaction as demonstrated by immunoblotting and cosedimentation experiments. Taken together, these findings suggest that interactions with actin play a dynamic role in the regulation of PMCA-mediated Ca2+ extrusion through the membrane. Our results provide further evidence of the activation-inhibition phenomenon as a property of many cytoskeleton-associated membrane proteins where the cytoskeleton is no longer restricted to a mechanical function but is dynamically involved in modulating the activity of integral proteins with which it interacts.
KW - Actin
KW - Cytoskeleton
KW - PMCA
KW - Regulation
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U2 - 10.1007/s12013-012-9467-6
DO - 10.1007/s12013-012-9467-6
M3 - Article
C2 - 23152090
AN - SCOPUS:84876187888
SN - 1085-9195
VL - 66
SP - 187
EP - 198
JO - Cell Biochemistry and Biophysics
JF - Cell Biochemistry and Biophysics
IS - 1
ER -