How many Ca(2)+ATPase isoforms are expressed in a cell type? A growing family of membrane proteins illustrated by studies in platelets.
Ca(2+) signaling plays a key role in normal and abnormal platelet functions. Understanding platelet Ca(2+) signaling requires the knowledge of proteins involved in this process. Among these proteins are Ca(2+)ATPases or Ca(2+) pumps that deplete the cytosol of Ca(2+) ions. Here, we will particularly focus on two Ca(2+) pump families: the plasma membrane Ca(2+)ATPases (PMCAs) that extrude cytosolic Ca(2+) towards the extracellular medium and the sarco/endoplasmic reticulum Ca(2+)ATPases (SERCAs) that pump Ca(2+) into the endoplasmic reticulum (ER). In the present review, we will summarize data on platelet Ca(2+)ATPases including their identification and biogenesis. First of all, we will present the Ca(2+)ATPase genes and their isoforms expressed in platelets. We will especially focus on a member of the SERCA family, SERCA3, recently found to give rise to a number of species-specific isoforms. Next, we will describe the differences in Ca(2+)ATPase patterns observed in human and rat platelets. Last, we will analyze how the expression of Ca(2+)ATPase isoforms changes during megakaryocytic maturation and show that megakaryocytopoiesis is associated with a profound reorganization of the expression and/or activity of Ca(2+)ATPases. Taken together, these data provide new aspects of investigations to better understand normal and abnormal platelet Ca(2+) signaling.
Bobe
R
R
INSERM U.689 E6, IFR139 Lariboisière, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France.
Bredoux
R
R
Corvazier
E
E
Lacabaratz-Porret
C
C
Martin
V
V
Kovács
T
T
Enouf
J
J
D000818:Animals; D001792:Blood Platelets / Q000201:enzymology* / Q000502:physiology; D000252:Calcium-Transporting ATPases / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D006801:Humans; D007527:Isoenzymes; D008533:Megakaryocytes / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D051381:Rats; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D013045:Species Specificity; D034061:Thrombopoiesis
C506951:Atp2a3 protein, rat; D007527:Isoenzymes; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; C506949:ATP2A3 protein, human; D000252:Calcium-Transporting ATPases