Evidence for a fourth rat isoform of the plasma membrane calcium pump in the kidney

This study was conducted to identify plasma membrane Ca 2+ -transporting ATPases present in rat kidney. Characterization of the cDNAs of the plasma membrane Ca 2+ -ATPases revealed a family of proteins with regions of highly conserved amino acid sequence. To examine the extent of the diversity of rat renal plasma membrane Ca 2+ -ATPases, we used the polymerase chain reaction to detect additional gene products in rat kidney mRNA that shared these conserved regions. Sequences corresponding to three previously known rat plasma membrane Ca 2+ -ATPases were obtained. In addition, we found sequence corresponding to a new putative plasma membrane Ca 2+ -ATPase. Our results demonstrate that the rat kidney contains at least four different plasma membrane Ca 2+ -ATPases and the complexity of this multigene family is greater than previously thought.