Expression and Activity of the Ca²⁺-ATPase Enzyme in Human Neonatal Erythrocytes

Abstract

The plasma membrane Ca²⁺-ATPase (PMCA) is one of the main regulators of Ca²⁺ homeostasis. We studied the perinatal alteration of the abundance and the activity of PMCA molecules in human erythrocytes in pre-term and full-term neonates and children at the age of 1–4 years. The lower abundance of the 4b isoform was associated with lower enzyme activity in full-term neonates compared to children. Although the number of PMCA molecules was higher in pre-term neonates, their total PMCA activities were identical to those of full-term neonates. Our findings suggest that the abundance of PMCA molecules changes during the perinatal development. The same activity at higher enzyme molecule numbers might indicate a potential immaturity of the enzyme in the pre-term infant.

Changes in Erythrocyte Glutathione and Plasma Membrane Calcium Pump in Preterm Newborns Treated Antenatally with MgSO₄

“…Our data demonstrated that while the main isoform appears to be PMCA4, the PMCA1 isoform is also represented in the erythrocyte ghosts. It extends the results obtained by Kocsis et al [24] , which using the PMCA4b-specific antibody showed this protein as an exclusive in erythrocytes of preterm newborn. In the control group, the PMCA1 amount was higher at birth and decreased slightly after 24 h, reaching the same level as the Mg-treated one.…”

“…After 24 h, the total amount of PMCA in control erythrocyte ghosts declined, but increased both basal and CaM-stimulated activity. These results could confirm that some of the enzyme molecules in preterm controls may exist in an inactive form, as suggested by others [24] . In contrary, at the same time in the Mg-treated group the higher amount of PMCA correlated with the augmented activity of the enzyme.…”

Developmental changes in Ca2+ homeostasis and contractility in gallbladder smooth muscle

“…In contrast, in hippocampal neurons, all major Ca 2ϩ extrusion systems are strongly upregulated during the first 2 wk of postnatal development as a consequence of changes in the expression and cellular localization of different isoforms of Ca 2ϩ pumps and exchangers (18). Human neonatal erythrocytes have fewer PMCA molecules, which also exhibit reduced PMCA activity compared with children erythrocytes, indicating that postnatal PMCA undergo developmental changes postnatally (22).…”

The Plasma Membrane Calcium ATPasesand Their Role as Major New Players in Human Disease

“…Human erythrocyte PMCA is composed primarily of PMCA4, with PMCA1 expression also having been identified (188,352). PMCA activity declines as red blood cells age in line with increasing glycated hemoglobin, which may make them prone to Ca 2ϩ overload and earmark them for clearance (207).…”