Structure, function and subcellular localization of a human platelet Ca2+-ATPase.
Human platelets contain a Ca2+-ATPase in internal membranes that is essential for Ca2+ homeostasis. This Ca2+ pump has enzymatic properties quite similar to the sarcoplasmic reticulum (SR) Ca2+ pumps. Antibodies against the SR Ca2+ pump crossreact with the human platelet protein. However, the platelet Ca2+-ATPase is approximately 10 kD larger than the SR pumps and exhibits a larger mRNA coding for the protein in a megakaryocyte tumor cell line. In addition, the platelet Ca2+-pump may be localized in specialized internal membrane structures that function in Ca2+ uptake and release. These results suggest that the platelet Ca2+-ATPase may represent a new class of internal membrane Ca2+-pumps.
Dean
W L
WL
Department of Biochemistry, University of Louisville, Kentucky.
D000906:Antibodies; D001693:Biological Transport, Active; D001792:Blood Platelets / Q000201:enzymology*; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000097:blood* / Q000302:isolation & purification / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D007425:Intracellular Membranes / Q000201:enzymology* / Q000378:metabolism; D012333:RNA, Messenger; D012519:Sarcoplasmic Reticulum / Q000201:enzymology / Q000378:metabolism; D014407:Tumor Cells, Cultured
D000906:Antibodies; D012333:RNA, Messenger; D000252:Calcium-Transporting ATPases; D002118:Calcium