The domain within your query sequence starts at position 1483 and ends at position 1671; the E-value for the PI3Ka domain shown below is 2.11e-54.

KDNVNLAWSISPYLAVQLPARFKNTEAIGNEVTRLVRLDPGAVSDVPEAIKFLVTWHTID
ADAPELSHVLCWAPTDPPTGLSYFSSMYPPHPLTAQYGVKVLRSFPPDAILFYIPQIVQA
LRYDKMGYVREYILWAAAKSQLLAHQFIWNMKTNIYLDEEGHQKDPDIGDLLEQLVEEIT
GSLSGPAKD

PI3Ka

Phosphoinositide 3-kinase family, accessory domain (PIK domain)

• SMART accession number: SM00145
• Description: PIK domain is conserved in all PI3 and PI4-kinases. Its role is unclear but it has been suggested to be involved in substrate presentation.
• Interpro abstract (IPR001263):

  Phosphatidylinositol 3-kinase (PI3K) ( EC 2.7.1.137 ) is an enzyme that phosphorylates phosphoinositides on the 3-hydroxyl group of the inositol ring. The role of the accessory domain of phosphoinositide 3-kinase (PI3-kinase) is unclear. It may be involved in substrate presentation [ (PUBMED:8248783) ].

There are 6540 PI3Ka domains in 6534 proteins in SMART's nrdb database.

Cellular role (predicted cellular role)

Binding / catalysis: unknown

Literature (relevant references for this domain)

Primary literature is listed below; Automatically-derived, secondary literature is also avaliable.

• Walker EH, Perisic O, Ried C, Stephens L, Williams RL
• Structural insights into phosphoinositide 3-kinase catalysis and signalling.
• Nature. 1999; 402: 313-20

Phosphoinositide 3-kinases (PI3Ks) are ubiquitous lipid kinases that function both as signal transducers downstream of cell-surface receptors and in constitutive intracellular membrane and protein trafficking pathways. All PI3Ks are dual-specificity enzymes with a lipid kinase activity which phosphorylates phosphoinositides at the 3-hydroxyl, and a protein kinase activity. The products of PI3K-catalysed reactions, phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3), PtdIns(3,4)P2 and PtdIns(3)P, are second messengers in a variety of signal transduction pathways, including those essential to cell proliferation, adhesion, survival, cytoskeletal rearrangement and vesicle trafficking. Here we report the 2.2 A X-ray crystallographic structure of the catalytic subunit of PI3Kgamma, the class I enzyme that is activated by heterotrimeric G-protein betagamma subunits and Ras. PI3Kgamma has a modular organization centred around a helical-domain spine, with C2 and catalytic domains positioned to interact with phospholipid membranes, and a Ras-binding domain placed against the catalytic domain where it could drive allosteric activation of the enzyme.

• Domin J, Waterfield MD
• Using structure to define the function of phosphoinositide 3-kinase family members.
• FEBS Lett. 1997; 410: 91-5

• Toker A, Cantley LC
• Signalling through the lipid products of phosphoinositide-3-OH kinase.
• Nature. 1997; 387: 673-6

When a stimulatory agonist molecule binds at the exterior of the cell membrane, a second messenger transduces the signal to the interior of the cell. Second messengers can be derived from phospholipids in the membrane by the action of the enzymes phospholipase C or phosphoinositide-3-OH kinase (PI(3)K). PI(3)K is a key player in many cellular responses, including the movement of organelle membranes, shape alteration through rearrangement of cytoskeletal actin, transformation and chemotaxis. But how PI(3)K mediates these responses is only now becoming clear.

• Vanhaesebroeck B, Leevers SJ, Panayotou G, Waterfield MD
• Phosphoinositide 3-kinases: a conserved family of signal transducers.
• Trends Biochem Sci. 1997; 22: 267-72

Phosphoinositide 3-kinases (PI3Ks) generate lipids that are implicated in receptor-stimulated signalling and in the regulation of membrane traffic. Several distinct classes of PI3Ks have now been identified that have been conserved throughout eukaryotic evolution. Potential signalling pathways downstream of PI3Ks have been elucidated and PI3K function is now being characterised in several model organisms.

• Kapeller R, Cantley LC
• Phosphatidylinositol 3-kinase.
• Bioessays. 1994; 16: 565-76

Currently, a central question in biology is how signals from the cell surface modulate intracellular processes. In recent years phosphoinositides have been shown to play a key role in signal transduction. Two phosphoinositide pathways have been characterized, to date. In the canonical phosphoinositide turnover pathway, activation of phosphatidylinositol-specific phospholipase C results in the hydrolysis of phosphatidylinositol 4,5-bisphosphate and the generation of two second messengers, inositol 1,4,5-trisphosphate and diacylglycerol. The 3-phosphoinositide pathway involves protein-tyrosine kinase-mediated recruitment and activation of phosphatidylinositol 3-kinase, resulting in the production of phosphatidylinositol 3,4-bisphosphate and phosphatidylinositol 3,4,5-trisphosphate. The 3-phosphoinositides are not substrates of any known phospholipase C, are not components of the canonical phosphoinositide turnover pathway, and may themselves act as intracellular mediators. The 3-phosphoinositide pathway has been implicated in growth factor-dependent mitogenesis, membrane ruffling and glucose uptake. Furthermore the homology of the yeast vps34 with the mammalian phosphatidylinositol 3-kinase has suggested a role for this pathway in vesicular trafficking. In this review the different mechanisms employed by protein-tyrosine kinases to activate phosphatidylinositol 3-kinase, and its involvement in the signaling cascade initiated by tyrosine phosphorylation, are examined.

• Flanagan CA, Schnieders EA, Emerick AW, Kunisawa R, Admon A, Thorner J
• Phosphatidylinositol 4-kinase: gene structure and requirement for yeast cell viability.
• Science. 1993; 262: 1444-8

Phosphatidylinositol (PtdIns) 4-kinase catalyzes the first step in the biosynthesis of PtdIns-4,5-bisphosphate (PtdIns[4,5]P2). Hydrolysis of PtdIns[4,5]P2 in response to extracellular stimuli is thought to initiate intracellular signaling cascades that modulate cell proliferation and differentiation. The PIK1 gene encoding a PtdIns 4-kinase from the yeast Saccharomyces cerevisiae was isolated by polymerase chain reaction (PCR) with oligonucleotides based on the sequence of peptides derived from the purified enzyme. The sequence of the PIK1 gene product bears similarities to that of PtdIns 3-kinases from mammals (p110) and yeast (Vps34p). Expression of PIK1 from a multicopy plasmid elevated PtdIns 4-kinase activity and enhanced the response to mating pheromone. A pik1 null mutant was inviable, indicating that PtdIns4P and presumably PtdIns[4,5]P2 are indispensable phospholipids.

Metabolism (metabolic pathways involving proteins which contain this domain)

% proteins involved	KEGG pathway ID	Description
8.46	map04070	Phosphatidylinositol signaling system
6.98	map00562	Inositol phosphate metabolism
3.05	map05222	Small cell lung cancer
3.05	map04664	Fc epsilon RI signaling pathway
3.05	map05210	Colorectal cancer
3.05	map05213	Endometrial cancer
3.05	map04370	VEGF signaling pathway
3.05	map04620	Toll-like receptor signaling pathway
3.05	map04662	B cell receptor signaling pathway
3.05	map05212	Pancreatic cancer
3.05	map04630	Jak-STAT signaling pathway
3.05	map05220	Chronic myeloid leukemia
3.05	map04210	Apoptosis
3.05	map04510	Focal adhesion
3.05	map04670	Leukocyte transendothelial migration
3.05	map04910	Insulin signaling pathway
3.05	map05215	Prostate cancer
3.05	map05214	Glioma
3.05	map04012	ErbB signaling pathway
3.05	map04810	Regulation of actin cytoskeleton
3.05	map04150	mTOR signaling pathway
3.05	map04660	T cell receptor signaling pathway
3.05	map05211	Renal cell carcinoma
3.05	map05221	Acute myeloid leukemia
3.05	map04930	Type II diabetes mellitus
3.05	map05223	Non-small cell lung cancer
3.05	map05218	Melanoma
3.05	map04650	Natural killer cell mediated cytotoxicity
3.05	map04914	Progesterone-mediated oocyte maturation
2.26	map04140	Regulation of autophagy

This information is based on mapping of SMART genomic protein database to KEGG orthologous groups. Percentage points are related to the number of proteins with PI3Ka domain which could be assigned to a KEGG orthologous group, and not all proteins containing PI3Ka domain. Please note that proteins can be included in multiple pathways, ie. the numbers above will not always add up to 100%.

Structure (3D structures containing this domain)

3D Structures of PI3Ka domains in PDB

PDB code	Title
1e7u	Structure determinants of phosphoinositide 3-kinase inhibition by wortmannin, LY294002, quercetin, myricetin and staurosporine
1e7v	Structure determinants of phosphoinositide 3-kinase inhibition by wortmannin, LY294002, quercetin, myricetin and staurosporine
1e8w	Structure determinants of phosphoinositide 3-kinase inhibition by wortmannin, LY294002, quercetin, myricetin and staurosporine
1e8x	STRUCTURAL INSIGHTS INTO PHOSHOINOSITIDE 3-KINASE ENZYMATIC MECHANISM AND SIGNALLING
1e8y	Structure determinants of phosphoinositide 3-kinase inhibition by wortmannin, LY294002, quercetin, myricetin and staurosporine
1e8z	Structure determinants of phosphoinositide 3-kinase inhibition by wortmannin, LY294002, quercetin, myricetin and staurosporine
1e90	Structure determinants of phosphoinositide 3-kinase inhibition by wortmannin, LY294002, quercetin, myricetin and staurosporine
1he8	Ras G12V - PI 3-kinase gamma complex
2a4z	Crystal Structure of human PI3Kgamma complexed with AS604850
2a5u	Crystal Structure of human PI3Kgamma complexed with AS605240
2chw	A pharmacological map of the PI3-K family defines a role for p110 alpha in signaling: The structure of complex of phosphoinositide 3- kinase gamma with inhibitor PIK-39
2chx	A pharmacological map of the PI3-K family defines a role for p110alpha in signaling: The structure of complex of phosphoinositide 3-kinase gamma with inhibitor PIK-90
2chz	A pharmacological map of the PI3-K family defines a role for p110alpha in signaling: The structure of complex of phosphoinositide 3-kinase gamma with inhibitor PIK-93.
2rd0	Structure of a human p110alpha/p85alpha complex
2v4l	complex of human phosphoinositide 3-kinase catalytic subunit gamma ( p110 gamma) with PIK-284
2wxf	The crystal structure of the murine class IA PI 3-kinase p110delta in complex with PIK-39.
2wxg	The crystal structure of the murine class IA PI 3-kinase p110delta in complex with SW13.
2wxh	The crystal structure of the murine class IA PI 3-kinase p110delta in complex with SW14.
2wxi	The crystal structure of the murine class IA PI 3-kinase p110delta in complex with SW30.
2wxj	The crystal structure of the murine class IA PI 3-kinase p110delta in complex with INK654.
2wxk	The crystal structure of the murine class IA PI 3-kinase p110delta in complex with INK666.
2wxl	The crystal structure of the murine class IA PI 3-kinase p110delta in complex with ZSTK474.
2wxm	The crystal structure of the murine class IA PI 3-kinase p110delta in complex with DL06.
2wxn	The crystal structure of the murine class IA PI 3-kinase p110delta in complex with DL07.
2wxo	The crystal structure of the murine class IA PI 3-kinase p110delta in complex with AS5.
2wxp	The crystal structure of the murine class IA PI 3-kinase p110delta in complex with GDC-0941.
2wxq	The crystal structure of the murine class IA PI 3-kinase p110delta in complex with AS15.
2wxr	The crystal structure of the murine class IA PI 3-kinase p110delta.
2x38	The crystal structure of the murine class IA PI 3-kinase p110delta in complex with IC87114.
2x6f	THE CRYSTAL STRUCTURE OF THE DROSOPHILA CLASS III PI3-KINASE VPS34 IN COMPLEX WITH 3-METHYLADENINE
2x6h	THE CRYSTAL STRUCTURE OF THE DROSOPHILA CLASS III PI3-KINASE VPS34
2x6i	THE CRYSTAL STRUCTURE OF THE DROSOPHILA CLASS III PI3-KINASE VPS34 IN COMPLEX WITH PIK-90
2x6j	THE CRYSTAL STRUCTURE OF THE DROSOPHILA CLASS III PI3-KINASE VPS34 IN COMPLEX WITH PIK-93
2x6k	THE CRYSTAL STRUCTURE OF THE DROSOPHILA CLASS III PI3-KINASE VPS34 IN COMPLEX WITH PI-103
2y3a	Crystal structure of p110beta in complex with icSH2 of p85beta and the drug GDC-0941
3apc	Crystal structure of human PI3K-gamma in complex with CH5132799
3apd	Crystal structure of human PI3K-gamma in complex with CH5108134
3apf	Crystal structure of human PI3K-gamma in complex with CH5039699
3csf	Crystal structure of PI3K p110gamma catalytical domain in complex with organoruthenium inhibitor DW2
3cst	Crystal structure of PI3K p110gamma catalytical domain in complex with organoruthenium inhibitor E5E2
3dbs	Structure of PI3K gamma in complex with GDC0941
3dpd	Achieving multi-isoform PI3K inhibition in a series of substituted 3,4-Dihydro-2H-benzo[1,4]oxazines
3ene	Complex of PI3K gamma with an inhibitor
3hhm	Crystal structure of p110alpha H1047R mutant in complex with niSH2 of p85alpha and the drug wortmannin
3hiz	Crystal structure of p110alpha H1047R mutant in complex with niSH2 of p85alpha
3ibe	Crystal Structure of a Pyrazolopyrimidine Inhibitor Bound to PI3 Kinase Gamma
3ihy	Human PIK3C3 crystal structure
3l08	Structure of Pi3K gamma with a potent inhibitor: GSK2126458
3l13	Crystal Structures of Pan-PI3-Kinase and Dual Pan-PI3-Kinase/mTOR Inhibitors
3l16	Discovery of (thienopyrimidin-2-yl)aminopyrimidines as Potent, Selective, and Orally Available Pan-PI3-Kinase and Dual Pan-PI3-Kinase/mTOR Inhibitors for the Treatment of Cancer
3l17	Discovery of (thienopyrimidin-2-yl)aminopyrimidines as Potent, Selective, and Orally Available Pan-PI3-Kinase and Dual Pan-PI3-Kinase/mTOR Inhibitors for the Treatment of Cancer
3l54	Structure of Pi3K gamma with inhibitor
3lj3	PI3-kinase-gamma with a pyrrolopyridine-benzofuran inhibitor
3ls8	Crystal structure of human PIK3C3 in complex with 3-[4-(4-Morpholinyl)thieno[3,2-d]pyrimidin-2-yl]-phenol
3mjw	PI3 Kinase gamma with a benzofuranone inhibitor
3ml8	Discovery of the Highly Potent PI3K/mTOR Dual Inhibitor PF-04691502 through Structure Based Drug Design
3ml9	Discovery of the Highly Potent PI3K/mTOR Dual Inhibitor PF-04691502 through Structure Based Drug Design
3nzs	Structure-based Optimization of Pyrazolo -Pyrimidine and -Pyridine Inhibitors of PI3-Kinase
3nzu	Structure-based Optimization of Pyrazolo -Pyrimidine and -Pyridine Inhibitors of PI3-Kinase
3oaw	4-Methylpteridineones as Orally Active and Selective PI3K/mTOR Dual Inhibitors
3p2b	Crystal Structure of PI3K gamma with 3-(2-morpholino-6-(pyridin-3-ylamino)pyrimidin-4-yl)phenol
3pre	Quinazolines with intra-molecular hydrogen bonding scaffold (iMHBS) as PI3K/mTOR dual inhibitors.
3prz	Quinazolines with intra-molecular hydrogen bonding scaffold (iMHBS) as PI3K/mTOR dual inhibitors.
3ps6	Quinazolines with intra-molecular hydrogen bonding scaffold (iMHBS) as PI3K/mTOR dual inhibitors.
3qaq	Crystal structure of PI3K-gamma in complex with triazine-benzimidazole 1
3qar	Crystal structure of PI3K-gamma in complex with triazine-benzimidazole 32
3qjz	Crystal structure of PI3K-gamma in complex with benzothiazole 1
3qk0	Crystal structure of PI3K-gamma in complex with benzothiazole 82
3r7q	Structure-based design of thienobenzoxepin inhibitors of PI3- kinase
3r7r	Structure-based design of thienobenzoxepin inhibitors of PI3-Kinase
3s2a	Crystal structure of PI3K-gamma in complex with a quinoline inhibitor
3sd5	Crystal Structure of PI3K gamma with 5-(2,4-dimorpholinopyrimidin-6-yl)-4-(trifluoromethyl)pyridin-2-amine
3t8m	Rational Design of PI3K-alpha Inhibitors that Exhibit Selectivity Over the PI3K-beta Isoform
3tjp	Crystal Structure of PI3K gamma with N6-(3,4-dimethoxyphenyl)-2-morpholino-[4,5'-bipyrimidine]-2',6-diamine
3tl5	Discovery of GDC-0980: a Potent, Selective, and Orally Available Class I Phosphatidylinositol 3-Kinase (PI3K)/Mammalian Target of Rapamycin (mTOR) Kinase Inhibitor for the Treatment of Cancer
3zim	Discovery of a potent and isoform-selective targeted covalent inhibitor of the lipid kinase PI3Kalpha
3zvv	Fragment Bound to PI3KInase gamma
3zw3	Fragment based discovery of a novel and selective PI3 Kinase inhibitor
4a55	Crystal structure of p110alpha in complex with iSH2 of p85alpha and the inhibitor PIK-108
4ajw	Discovery and Optimization of New Benzimidazole- and Benzoxazole-Pyrimidone Selective PI3KBeta Inhibitors for the Treatment of Phosphatase and TENsin homologue (PTEN)-Deficient Cancers""
4anu	Complexes of PI3Kgamma with isoform selective inhibitors.
4anv	Complexes of PI3Kgamma with isoform selective inhibitors.
4anw	Complexes of PI3Kgamma with isoform selective inhibitors.
4anx	Complexes of PI3Kgamma with isoform selective inhibitors.
4aof	Selective small molecule inhibitor discovered by chemoproteomic assay platform reveals regulation of Th17 cell differentiation by PI3Kgamma
4bfr	Discovery and Optimization of Pyrimidone Indoline Amide PI3Kbeta Inhibitors for the Treatment of Phosphatase and TENsin homologue ( PTEN)-Deficient Cancers
4dk5	Crystal structure of human PI3K-gamma in complex with a pyridyl-triazine inhibitor
4ezj	Potent and Selective Inhibitors of PI3K-delta: Obtaining Isoform Selectivity from the Affinity Pocket and Tryptophan Shelf
4ezk	Potent and Selective Inhibitors of PI3K-delta: Obtaining Isoform Selectivity from the Affinity Pocket and Tryptophan Shelf
4ezl	Potent and Selective Inhibitors of PI3K-delta: Obtaining Isoform Selectivity from the Affinity Pocket and Tryptophan Shelf
4f1s	Crystal structure of human PI3K-gamma in complex with a pyridyl-triazine-sulfonamide inhibitor
4fa6	Design and Synthesis of a Novel Pyrrolidinyl Pyrido Pyrimidinone Derivative as a Potent Inhibitor of PI3Ka and mTOR
4fad	Design and Synthesis of a Novel Pyrrolidinyl Pyrido Pyrimidinone Derivative as a Potent Inhibitor of PI3Ka and mTOR
4fhj	Crystal Structure of PI3K-gamma in Complex with Imidazopyridine 2
4fhk	Crystal Structure of PI3K-gamma in Complex with Imidazopyridazine 19e
4fjy	Crystal structure of PI3K-gamma in complex with quinoline-indoline inhibitor 24f
4fjz	Crystal structure of PI3K-gamma in complex with pyrrolo-pyridine inhibitor 63
4flh	Crystal structure of human PI3K-gamma in complex with AMG511
4ful	PI3 Kinase Gamma bound to a pyrmidine inhibitor
4g11	X-ray structure of PI3K-gamma bound to a 4-(morpholin-4-yl)- (6-oxo-1,6-dihydropyrimidin-2-yl)amide inhibitor
4gb9	Potent and Highly Selective Benzimidazole Inhibitors of PI3K-delta
4hle	Compound 21 (1-alkyl-substituted 1,2,4-triazoles)
4hvb	Catalytic unit of PI3Kg in complex with PI3K/mTOR dual inhibitor PF-04979064
4j6i	Discovery of thiazolobenzoxepin PI3-kinase inhibitors that spare the PI3-kinase beta isoform
4jps	Co-crystal Structures of the Lipid Kinase PI3K alpha with Pan and Isoform Selective Inhibitors
4kz0	Structure of PI3K gamma with Imidazopyridine inhibitors
4kzc	Structure of PI3K gamma with Imidazopyridine inhibitors
4l1b	Crystal Structure of p110alpha complexed with niSH2 of p85alpha
4l23	Crystal Structure of p110alpha complexed with niSH2 of p85alpha and PI-103
4l2y	Crystal Structure of p110alpha complexed with niSH2 of p85alpha and compound 9d
4ovu	4OVU
4ovv	4OVV
4oys	4OYS
4ph4	4PH4
4ps3	Structure of PI3K gamma in complex with 1-[6-(5-methoxypyridin-3-yl)-1,3-benzothiazol-2-yl]-3-[2-(1-propyl-1H-imidazol-4-yl)ethyl]urea
4ps7	Structure of PI3K gamma in complex with N-[6-(pyridin-3-yl)-1,3-benzothiazol-2-yl]acetamide
4ps8	Structure of PI3K gamma in complex with N-[6-(5,6-dimethoxypyridin-3-yl)-1,3-benzothiazol-2-yl]acetamide
4tuu	4TUU
4tv3	4TV3
4urk	4URK
4uwf	4UWF
4uwg	4UWG
4uwh	4UWH
4uwk	4UWK
4uwl	4UWL
4v0i	4V0I
4waf	4WAF
4wwn	4WWN
4wwo	4WWO
4wwp	4WWP
4xe0	4XE0
4xx5	4XX5
4xz4	4XZ4
4ykn	4YKN
4zop	4ZOP
5ae8	5AE8
5ae9	5AE9
5anl	5ANL
5dfz	5DFZ
5dxh	5DXH
5dxt	5DXT
5dxu	5DXU
5eds	5EDS
5enn	5ENN
5fi4	5FI4
5g2n	5G2N
5g55	5G55
5is5	5IS5
5itd	5ITD
5kc2	5KC2
5l72	5L72

Links (links to other resources describing this domain)

• INTERPRO: IPR001263