Differentiation of sarcoplasmic reticulum during cardiac myogenesis
The composition and function of fetal and mature sheep cardiac sarcoplasmic reticulum membranes were investigated. Phospholamban, a major phosphoprotein in the mature sarcoplasmic reticulum membranes, was present in early stages of cardiac myogenesis. This fetal form of phospholamban was phosphorylated by cAMP-dependent protein kinase but not in the presence of Ca/sup 2 +/ and calmodulin. /sup 35/Ca/sup 2 +/ uptake and Ca/sup 2 +/-dependent ATPase activity were low in fetal sarcoplasmic reticulum compared with the adult controls, although the apparent affinities for Ca/sup 2 +/ were similar. Sarcoplasmic reticulum vesicles isolated at all developmental stages had very low levels of plasma membrane and mitochondrial contamination. Sarcoplasmic reticulum /sup 45/Ca/sup 2 +/ uptake and Ca/sup 2 +/-dependent. ATPase activities were not affected by micromolar concentrations of vanadate, and the accumulated /sup 45/Ca/sup 2 +/ could not be released by the addition of NaCl. The amount of both the 110- and 55-kDa protein bands, identified with pecific antibodies as Ca/sup 2 +/-ATPase and calsequestrin, respectively, was low in early stages of cardiac myogenesis. Age-related differences in the Ca/sup 2 +/ transport properties of cardiac sarcoplasmic reticulum and in the amount of the Ca/sup 2 +/-ATPase and calsequestrin may explain alterations in the regulation of intracellular Ca/sup 2 +/ concentrations in the fetal heart. This may contribute to the developmental changes in myocardial function.
- Research Organization:
- Univ. of Toronto, Ontario
- OSTI ID:
- 6351950
- Journal Information:
- Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 252:1; ISSN AJPHA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Ca release and ryanodine binding in sarcoplasmic reticulum during cardiac myogenesis
Chromosome mapping of five human cardiac and skeletal muscle sarcoplasmic reticulum protein genes
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
AGE DEPENDENCE
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
ATP
ATP-ASE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CALCIUM 45
CALCIUM CHLORIDES
CALCIUM COMPOUNDS
CALCIUM HALIDES
CALCIUM ISOTOPES
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
DATA
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON MICROSCOPY
ELECTROPHORESIS
ENZYME ACTIVITY
ENZYMES
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HALIDES
HALOGEN COMPOUNDS
HEART
HYDROLASES
IMMUNE REACTIONS
INFORMATION
INTERMEDIATE MASS NUCLEI
ISOTOPES
LIGHT NUCLEI
MAMMALS
MEMBRANE TRANSPORT
MICROSCOPY
NUCLEI
NUCLEOTIDES
NUMERICAL DATA
ODD-ODD NUCLEI
ONTOGENESIS
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
PHOSPHOHYDROLASES
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOSPHORYLATION
RADIOISOTOPES
RUMINANTS
SARCOPLASMIC RETICULUM
SHEEP
TRANSMISSION ELECTRON MICROSCOPY
VERTEBRATES