The biosynthesis of sarcoplasmic reticulum.
Muscle differentiation provides a slow-motion picture of the assembly of highly specialized sarcoplasmic reticulum endowed with Ca2+ transport activity from its constituents. During development of chicken embryo pectoralis muscle, the sarcoplasmic reticulum evolves from the rough endoplasmic reticulum of myoblasts by insertion of Ca2+ transport ATPase molecules synthesized on membrane-bound polysomes into the phospholipid-rich endoplasmic reticulum membrane. The process continues until the Ca2+ ATPase content of the membrane approaches physical saturation. The rate of synthesis of Ca2+ ATPase sharply increases after fusion of myoblasts into multinucleated myotubes and the accumulation of sarcoplasmic reticulum and myofibrillar proteins follows a roughly similar time course. The regulation of Ca2+ ATPase synthesis during development involves myogenic as well as neurogenic mechanisms. There are indications that changes in intracellular free Ca2+ concentration may play a role in this regulation.
D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002474:Cell-Free System; D002645:Chickens; D008074:Lipoproteins / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D024510:Muscle Development; D009132:Muscles / Q000294:innervation; D010743:Phospholipids / Q000378:metabolism; D014176:Protein Biosynthesis; D012519:Sarcoplasmic Reticulum / Q000378:metabolism* / Q000648:ultrastructure
D002135:Calcium-Binding Proteins; D008074:Lipoproteins; D008563:Membrane Lipids; D008565:Membrane Proteins; D010743:Phospholipids; D000252:Calcium-Transporting ATPases