Calcium channels and their role in regenerative medicine

Table 2 Calcium signaling toolkit

Component of toolkit	Name of calcium signaling toolkit components
Cell-surface receptors	G protein-coupled receptors and protein tyrosine kinase receptors such as muscarinic, bradykinin B2, cholecystokinin, α, β-adrenergic, P2X and P2Y, angiotensin II, Ca2+-sensing receptor, chemokine, metabotrophic glutamate, serotonin, oxytocin, epidermal growth factor receptor, and platelet-derived growth factor[46,106,107]
Calcium channels	Voltage-gated channels (Cav1.1 to 1.4 [L-type], Cav2.1 to 2.3 [N-, P/Q- and R-type] and Cav3.1 to 3.3 [T-type]) and two-pore channels (TPCs)[46], voltage-gated K+ channel, Ca2+-activated K+ channel, ATP-sensitive K+ channels, TRPC1-7 ORAI1-3, IP3R, and RyR2[108-110]
Calcium pumps and exchangers	Na+/Ca2+ exchangers, Na+/Ca2+-K+ exchangers, plasma membrane Ca2+-ATPase (PMCA) and sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) pumps[46,111]
Calcium buffers (Ca2+-binding proteins)	Cytoplasmic buffers (PV [parvalbumin], CB [calbindin D-28k], and calretinin)[112] and buffers in lumen of the endoplasmic reticulum (ER) (calsequestrin, calreticulin, glucose-regulated protein [GRP] 78 and GRP94), ERp72, and mitochondrial calcium uniporter (MCU), Golgi buffers (Cab45, CALNUC P54/NEFA[46,113], troponin C, myosin, calmodulin, and sarcolemma (cellular buffers in myocytes)[114]
Calcium sensors	EF-hand (CaM, TnC, calpains, miro1-2, S100A1-14, S100B, S100C, S100P, NCS-1, hippocalcin, neurocalcin, recoverin, VILIP1-3, GCAP1-3, MICU1 etc.) or C2 Ca2+-binding domains (annexin 1-13, otoferin, protein kinase C, RASAL etc.)[46], ER Ca2+ sensors STIM1 and STIM2[115]