Shuffling the cards in signal transduction: Calcium, arachidonic acid and mechanosensitivity

Table 1 Properties of phospholipase A2 groups[36,41,43,45,46,54,55,85]

Group	Location	Size (kDa)	Common sources	Calcium requirement
I	Secreted	13-15	Cobra, human	mmol/L
II	Secreted	13-15	Viper, mouse, human	mmol/L
III	Secreted	16-18	Bee, lizard, scorpion, human	mmol/L
IV	Cytosolic	85	Human	< μmol/L
V	Secreted	14	Human	No
VI	Cytosolic	80-85	Human	No
VII	Cytosolic	40	Human, bovine	No
	Secreted	45	Human, bovine	No
VIII	Cytosolic	29	Human	No
IX	Secreted	14	Marine snail	< mmol/L
X	Secreted	14	Human	mmol/L
XI	Secreted	12-13	Green rice	mmol/L
Other	Secreted	14-15	Streptomyces (Bacteria)	mmol/L
	Cytosolic	93	Sporothrix schenckii (Fungi)	< μmol/L
	Secreted	10	Parvovirus	mmol/L

Table 2 No. of transient receptor potential genes in different organisms[60,61,63,67-70,79,88]

Organism	TRP
Arabidopsis (Angiospermae)	0
Chlamydomonas (Chlorophyta)	19
Fungi (unicellular and multicellular)	3
Monosiga brevicollis (Choanoflagellates)	5
Caenorabditis elegans (Nematoda)	17
Drosophila melanogaster (Insecta)	13
Ciona intestinalis (sea squirt, Ascidiacea)	27
Fugu rubripes (Puffer fish)	25
Danio rerio (Zebrafish)	27
Mus musculus (Mammalia)	28
Homo sapiens (Mammalia)	27

Transient receptor potential (TRP) genes are also found in the genomes of a number of protists not shown in table (see text).