Phospholemman expression is high in the newborn rabbit heart and declines with postnatal maturation.
Phospholemman (PLM) is a small sarcolemmal protein that modulates the activities of Na(+)/K(+)-ATPase and the Na(+)/Ca(2+) exchanger (NCX), thus contributing to the maintenance of intracellular Na(+) and Ca(2+) homeostasis. We characterized the expression and subcellular localization of PLM, NCX, and the Na(+)/K(+)-ATPase alpha1-subunit during perinatal development. Western blotting demonstrates that PLM (15kDa), NCX (120kDa), and Na(+)/K(+)-ATPase alpha-1 (approximately 100kDa) proteins are all more than 2-fold higher in ventricular membrane fractions from newborn rabbit hearts (1-4-day old) compared to adult hearts. Our immunocytochemistry data demonstrate that PLM, NCX, and Na(+)/K(+)-ATPase are all expressed at the sarcolemma of newborn ventricular myocytes. Taken together, our data indicate that PLM, NCX, and Na(+)/K(+)-ATPase alpha-1 proteins have similar developmental expression patterns in rabbit ventricular myocardium. Thus, PLM may have an important regulatory role in maintaining cardiac Na(+) and Ca(2+) homeostasis during perinatal maturation.
Srivastava
Shekhar
S
Department of Pharmacology, The Skirball Institute, New York University School of Medicine, New York, NY 10016, USA.
Cala
Steven E
SE
Coetzee
William A
WA
Artman
Michael
M
D000818:Animals; D000831:Animals, Newborn; D006128:Growth; D008565:Membrane Proteins / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D011817:Rabbits; D019831:Sodium-Calcium Exchanger / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D008565:Membrane Proteins; D010750:Phosphoproteins; D019831:Sodium-Calcium Exchanger; C110374:sodium-calcium exchanger 1; C069141:phospholemman; D000254:Sodium-Potassium-Exchanging ATPase