. 2007 Aug;121(4):448–461. doi: 10.1111/j.1365-2567.2007.02663.x

Table 1.

Main characteristics of the members of the PI3K family

Class	Subclass	Catalytic subunit	Adaptor/ Regulatory subunits	Regulated by	Distribution	In vitro lipid products	Functions for selective inhibitors	Organization with licences
I	A	p110α	p85α, p85β,	RTK^a	Ubiquitous	PI(3)P^b,	Development^c ¹⁴,	Eli Lilly
			p55α, p55γ, p50α			PI(3,4)P2^d,	Human cancer^e ¹¹⁶,	Iconix
						PI(3,4,5)P3^f	Myocardial contractility¹¹⁷	Echelon
								Astra Zeneca
								Wyeth
								PIramed
								More^g
		p110β	p85α, p85β,	RTK^a,	Ubiquitous	PI(3)P^b,	Development^c ¹⁵,	Kinacia
			p55α, p55γ, p50α	GPCR^h		PI(3,4)P2^d	Insulin signalling¹¹⁸,
						PI(3,4,5)P3^f	Motility¹¹⁹,
							Phagocytosis¹²⁰,
							Thrombus formation¹²¹,
		p110δ	p85α, p85β,	RTK^a	Leucocytesⁱ	PI(3)P^b,	Immunity²⁴,	ICOS
			p55α, p55γ, p50α			PI(3,4)P2^d,	Cytokine receptor signalling¹²²,	PIramed
						PI(3,4,5)P3^f	B-cell development²⁴,
							B-cell migration³⁸,
							T-cell development¹²³,
							Cell proliferation¹²⁴,
							B- and T-cell antigenreceptor signalling²⁴,
							Smooth muscle tone andhypertension¹²⁵,
							Neutrophil migration and burst⁴⁰
	B	p110γ	p101, p87^PIKAP	GPCR^h	Myeloidⁱ	PI(3)P^b,	Thymocyte development¹²⁶,	Novartis
						PI(3,4)P2^d,	T cell development¹²³,	Bayer
						PI(3,4,5)P3^f	T cell migration³⁸,	Pfizer
							Neutrophil migration¹²⁶,	Serono
							Macrophage and dendritic cell migration³⁷,	Targegen
							Mast cell degranulation²⁹,	Calbiochem
							Neutrophil burst⁴⁰,
							Insulin secretion¹²⁷,
							Myocardial contractility¹¹⁷
II		C2α	Clathrin	RTK^a	Widespread	PI(3)P^b,	Vesicle trafficking⁹,
				GPCR^h, IR^j		PI(3,4)P2^d	Insulin signalling¹²⁸,
							Cell survival¹²⁹,
							Vascular smooth musclecontraction¹³⁰
		C2β	Clathrin	RTK^a,	Widespread	PI(3)P^b,	Vesicle trafficking¹³¹,
				GPCR^h, IR^j		PI(3,4)P2^d	Cell migration¹³²^,¹³³,
							Liver growth¹³⁴
		C2γ	Clathrin	?	Hepatic	PI(3)P^b,	Liver regeneration¹³⁵
						PI(3,4)P2^d
III		Vps34p	Vps15p	TLR^k, constitutive	Ubiquitous	PI(3)P^b	Toll-like receptor signalling¹³⁶,
							Receptor-independent membranetrafficking¹³⁷

Receptor tyrosine kinase

phosphatidyl inositol-3-monophosphate

deletion associated with defective mouse embryonic proliferation and death

phosphatidyl inositol-3,4-bisphosphate

mutated/amplified in human cancer

phosphatidyl inositol 3,4,5-trisphosphate

due to the high frequency of PIK3CA mutations in human cancer, extensive research into selective inhibitors for this isoform have been carried out by many other institutions (Yamanouchi, Xinxiang Medical College, Semafore, Chiron, Zenyaku Kogyo, Boehringer, University of British Columbia)

G-protein coupled receptors

ⁱ

mainly, but also expressed in endothelial cells and others

integrin receptors

Toll-like receptors.