Ca2+ Sensors
Sensors are listed by classes and in some cases only selected members are shown. Information on Ca2+ signaling, ‘calcium signaling kit’ can be found at PMIDs 22435804, 18083096. References for the individual classes are in the sections dedicated to them. All references are provided in the main pathway diagram page. The genes in given classes are listed with aliases in parentheses, full names and links to gene report pages.

Calmodulin – a prominent Ca2+ sensor with a dumbbell-like structure whose lobes each house two EF-hand motif Ca2+ binding sites that have different affinities and kinetics for the metal ion. Calmodulin is transcribed from three chromosomes in humans and higher organisms; for more information, check main text and PMID 10884684.
Calm1 (caM, CAMI, CPVT4) – calmodulin 1
Calm2 – calmodulin 2
Calm3 – calmodulin 3

Synaptotagmins – transmembrane proteins that employ a C2 Ca2+ binding domain; metal coordination is provided by both the protein and membrane lipids. The better understood systems are listed below. For more information, check main text and PMIDs 20668007, 23060190.
Syt1 (SVP65, p65) – synaptotagmin 1
Syt7 (SYTVII, IPCA7) – synaptotagmin 7
Syt9 (sytIX) – synaptotagmin 9

Neuronal calcium sensors – the family comprises 14 members further subdivided into five classes; several are listed here. For more information, check main text and PMID 20668007.
Ncs1 (FLUP) – neuronal calcium sensor 1
Rcvrn (RCV1) – recoverin
Guca1a (Gcap1, COD3) – guanylate cyclase activator 1A
Guca1b (Gcap2, RP48) – guanylate cyclase activator 1b (retina)
Guca2b (uroguanylin) – guanylate cyclase activator 2b
KCnip1 (Kchip1) – potassium voltage-gated channel interacting protein 1
KCnip2 (Kchip2) – potassium voltage-gated channel interacting protein 2
KCnip3 (Kchip3, calsenilin) – potassium voltage-gated channel interacting protein 3
KCnip4 (Kchip4) – potassium voltage-gated channel interacting protein 4

Troponin – two family members, each comprising four EF hand Ca2+ binding domains, play important roles in the regulation of muscle contraction.
Tnnc1 – troponin C1, slow skeletal and cardiac type
Tnnc2 – troponin C2, fast skeletal type

CaBP family – the family is only represented in vertebrates and its members contain four EF hand Ca2+ binding motifs; a subset is better understood and are listed here. For more information, check main text and PMID 20668007.
Cabp1 (caldendrin) – calcium binding protein 1
Cabp2 – calcium binding protein 2
Cabp4 – calcium binding protein 4

S100 family –the family is considered an evolutionary newcomer, is only represented in vertebrates and is probably the largest group within the superfamily of EF-hand proteins; a subset is listed here. For more information, check main text and PMID 17964289.
S100a1 (S100-alpha) – S100 calcium binding protein A1
S100a4 – S100 calcium-binding protein A4
S100b – S100 calcium binding protein B