Intracellular Calcium Homeostasis Flashcards
what does calmodulin do
facilitates smooth muscle contraction
where is Ca+ stored
endoplasmic reticulum
what is highly expressed in skeletal and cardiac muscle
calsequestrin
calsequestrin is highly expressed where
skeletal and cardiac muscle
name some pumps involevd in the entry point for calcium
Ca2+ATPases
Voltage gated Ca2+ channes
Na+/Ca2+ exchanger
permeability transition pore
when does Ca2+ ATPase transfer calcium
after the contraction of a muscle
what are the two kinds of Ca2+ ATPase
PMCA
SERCA
what is the ratio of ions moved in PMCA
H+1:1Ca2+
what is the ratio of ions moved in SERCA
H+2:2Ca2+
PMCA moves 1 Ca”+ out of each cell for each
H+ATP hydrolysed
How can PMCA activity be increases
binding of calmodulin to the C-terminal domain
SERCA moves 2 Ca2+ into ___________ for each ATP hydrolysed
sarcoplasmic reticulum
What are the 2 mian sites in SERCA and what is their corresponding affinitys
E1 - high calcium affinity
E2 - low calcium affinity
How can SERCA be regulated
ATP and phospholamban
Na+/Ca2+ is alos known as what
NCX
What family does NCX belong to
Ca2+/cation antiporter super family
what is the ratio of ions moved in NCX
Na+3:1Ca2+
in voltage gated calcium channels, how many subunits are there
4
in voltage gated calcium channels, what are the subunits
alpha 1
B
alpha 2 delta
Gamma
in voltage gated calcium channels, what is the largest subunit
alpha 1
in voltage gated calcium channels, what subunit contains the ion selective residues (glutamine)
alpha 1
in voltage gated calcium channels, what contains the voltage sensor
alpha 1
in voltage gated calcium channels, where is the intracellular subunit
beta
in voltage gated calcium channels, what subunit is the extracellular subunit
alpha2delta
in voltage gated calcium channels, what subunit has two proteins joined by disulphide bridges
alpha2delta
in voltage gated calcium channels, what subunit has variable effects on channel function
gamma
