Molecular properties of excitation-contraction coupling proteins in infant and adult human heart tissues.
Excitation-contraction coupling (ECC) proteins in the human heart were characterized using human atrial tissues from different age groups. The samples were classified into one infant group (Group A: 0.2-7 years old) and three adult groups (Group B: 21-30; Group C: 41-49; Group D: 60-66). Whole homogenates (WH) of atrial tissues were assayed for ligand binding, 45Ca2+ uptake and content of ECC proteins by Western blotting. Equilibrium [3H]ryanodine binding to characterize the ryanodine receptor (RyR) of the sarcoplasmic reticulum (SR) showed that the maximal [3H]ryanodine binding (Bmax) to RyR was similar in all the age groups, but the dissociation constant (kd) of ryanodine was higher in the infant group than the adult groups. Oxalate-supported 45Ca2+ uptake into the SR, a function of the SR SERCA2a activity, was lower in the infant group than in the adult groups. Similarly, [3H]PN200-110 binding, an index of dihydropyridine receptor (DHPR) density, was lower in the infant group. Expression of calsequestrin and triadin assessed by Western blotting was similar in the infant and adult groups, but junctin expression was considerably higher in the adult groups. These differences in key ECC proteins could underlie the different Ca2+ handling properties and contractility of infant hearts.
Jung
Dai Hyun
DH
Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea.
Lee
Cheol Joo
CJ
Suh
Chang Kook
CK
You
Hye Jin
HJ
Kim
Do Han
DH
D000328:Adult; D000368:Aged; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000737:chemistry / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000737:chemistry / Q000378:metabolism; D002155:Calsequestrin / Q000737:chemistry* / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007223:Infant; D008297:Male; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000737:chemistry* / Q000378:metabolism; D009124:Muscle Proteins / Q000737:chemistry* / Q000378:metabolism; D009200:Myocardial Contraction; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism*; D012433:Ryanodine / Q000378:metabolism; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D013997:Time Factors
D020746:Calcium Channels, L-Type; D002135:Calcium-Binding Proteins; D002155:Calsequestrin; D002352:Carrier Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; D019837:Ryanodine Receptor Calcium Release Channel; C498269:TRDN protein, human; D012433:Ryanodine; D006899:Mixed Function Oxygenases; C419389:ASPH protein, human; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases; D002118:Calcium