The Involvement of Phospholipases A₂ in Asthma and Chronic Obstructive Pulmonary Disease

Table 1

Characteristics of structure and localization of human phospholipase A₂ enzymes. Adapted and modified from [1, 4]. The Roman numeral indicates the group, and the capital letter after the number indicates the subgroup.

Name	Members (human)	Molecular mass (kDa)	Relationship with Ca^2+	Catalytic site	Localization
Secretory; phospholipase A2 (sPLA2)	IB (sPLA2IB)	13–15			Secreted
	IIA (sPLA2IIA)	13–15			Secreted; membrane; secretory granules
	IID (sPLA2IID)	14-15			Secreted
	IIE (sPLA2IIE)	14-15			Secreted
	IIF (sPLA2IIF)	16-17			Secreted
	III (sPLA2III)	55	Dependent	Histidine/Aspartic acid	Secreted
	V (sPLA2V)	14			Secreted; Golgi apparatus; nuclear envelope; plasma membrane
	X (sPLA2X)	14			Secreted
	XIIA (sPLA2XIIA)	19			Secreted; cytoplasm
	XIIB (sPLA2XIIB, XIII)	20			Secreted
	IVA (cPLA2α)	85	Dependent		Nucleus; cytoplasmic vesicles
	IVB (cPLA2β)-three splice variants	114			Cytosol
Cytosolic phospholipase A2 (cPLA2)	IVC (cPLA2γ)	61	Independent		ER; Mitochondrium
	IVD (cPLA2δ)	92-93		Serine/Aspartic acid/Arginine	Cytosol; Cytoplasmic vesicle membrane; peripheral membrane protein; cytoplasmic side
	IVE (cPLA2ε)	96	Dependent		Cytosol; lysosome membrane; peripheral membrane protein
	IVF (cPLA2ζ)	95			Cytosol; lysosome membrane; peripheral membrane protein; cytoplasmic side
Ca^2+-independent phospholipase A2 (iPLA2)	VIA-(iPLA2β)-five splice variants	84–90			Cytosol
	VIB (iPLA2γ)-four splice variants	88–91			ER; peroxisomal and mitochondrial membrane
	VIC (iPLA2δ, NTE)	146	Independent	Serine	ER; single-pass type I membrane protein; cytoplasmic side
	VID (iPLA2ε, adiponutrin)	53			Membrane; single-pass type II membrane protein
	VIE (iPLA2ζ)	57			Lipid droplet membrane; single-pass type II membrane protein; cell membrane
	VIF (iPLA2η)	28			Cytoplasm
Acidic Ca^2+-independent phospholipase A2	aiPLA2	26	Independent	Serine	Cytoplasm; Lysosome
Lysosomal phospholipase A2	XV (LPLA2, LLPL, ACS)	45	Independent	Serine/Histidine/Aspartic acid	Secreted; Lysosome
PAF acetylhydrolase (PAF-AH) or Lipoprotein-associated phospholipase A2	VIIA (Lp-PLA2, Plasma PAF-AH)	45	Independent	Serine/Histidine/Aspartic acid	Secreted
	VIIB (PAF-AH II)	40			Cytoplasm
	VIIIA (PAF-AH Ib) α1 subunit	26			Cytoplasm
	VIIIB (PAF-AH Ib) α2 subunit	26			Cytoplasm
Adipose-specific phospholipase A2	XVI (H-Rev107)	18	Independent	Cystein/Histidine/Histidine	Cytoplasm, perinuclear region, Single-pass membrane protein

ER: endoplasmic reticulum; NTE: neuropathy target esterase.