Flashcards in CellSig8 - 10 Deck (10):
What is the Ca wave in the egg caused by?
Phospholipase C in the sperm
What is special about Ca as a signalling molecule?
Never created or destroyed - only its concentration is controlled
How is cytosolic Ca kept low?
Na-driven Ca exchanger (nerves/muscles), PMCA (PM Ca ATPase), SERCA (SER Ca ATPase), Ca uniporter (mitochondrion)
1+2 in types of muscle, 3 in non-muscle cells
What is thapsigargin?
Selectively inihibits SERCA activity
How is cytosolic Ca increased?
Voltage dependent Ca channels in PM, IP3-gated allow escape from ER, ryanodine receptors release Ca from sarcoplasmic reticulum
What inhibits the IP3 Ca release pathway?
Ethanol and caffeine - relaxants
Why is calmodulin very important?
1% of cell protein, activates MLCK, allows myosin head to interact and thus facilitates contraction of muscle
Outline MLCK cycle
Inactive + Ca-calmodulin > activated + auto-phosphrylation > fully active > Ca independent > dephosphorylation > inactive