regulation intracellular calcium Flashcards
what is different about Ca2+ to other ions
Unlike other ions (Na+, K+, Cl-) it is the CHEMICAL signal carried by Ca2+ that is important, not the electrical charge of the ion
what are the three kinds of calcium homeostasis
cellular calcium oscillates
serum calcium is fixed
bone calcium continiously changes
what are the major pathways for cellular Ca increase
Voltage gated calcium channels
Na-Ca exchanger
Receptor operated calcium channels
what does depletion of intracellular calcium stores activate
it activates calcium entry to subsequently refill the
emptied calcium stores (referred to as store-operated calcium entry)
what are the two key components for calcium re entry
a sensor of calcium store depletion and that when activated allows for calcium entry to refill the stores
what are the protiens that form the calcium pores on the plasma membrane
ORAI proteins
what are the proteins that sense the calcium stores are depleted
STIM proteins
do stim proteins have a low or high affinity calcium binding domain
low, they only bind to calcium, when calcium level are really high
mitochindria respond dynamically to calcium fluctuations, what does this mean
an increase in mitochondrial calcium allows the cells to adapt to sudden changes in energy demand by stimulating ATP production thereby providing more energy to the cell
Ca2+ accumulation by mitochondria is a common event in what
necrotic and apoptotic cell death
why is the outer mitochondrial membrane highly permeable to calcium
abundant expression of voltage-dependent anion channels
Ca entry into the IMM is favoured by what
the electrical and chemical gradient, and its exit was experimentally determined to be mediated
by a Na –dependent and independent pathways
