ID VATB2_MOUSE Reviewed; 511 AA. AC P62814; O09045; P50517; Q3TG74; Q3TL62; Q3TVK6; Q3TWR0; Q3U791; Q3U7C8; AC Q3U9Z0; Q3UAW7; DT 16-AUG-2004, integrated into UniProtKB/Swiss-Prot. DT 16-AUG-2004, sequence version 1. DT 24-JAN-2024, entry version 163. DE RecName: Full=V-type proton ATPase subunit B, brain isoform; DE Short=V-ATPase subunit B 2; DE AltName: Full=Endomembrane proton pump 58 kDa subunit; DE AltName: Full=Vacuolar proton pump subunit B 2; GN Name=Atp6v1b2; Synonyms=Atp6b2, Vat2; OS Mus musculus (Mouse). OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; OC Eutheria; Euarchontoglires; Glires; Rodentia; Myomorpha; Muroidea; Muridae; OC Murinae; Mus; Mus. OX NCBI_TaxID=10090; RN [1] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RX PubMed=8741845; DOI=10.1091/mbc.7.1.129; RA Laitala T., Howell M.L., Dean G.E., Vaananen H.K.; RT "Resorption-cycle-dependent polarization of mRNAs for different subunits of RT V-ATPase in bone-resorbing osteoclasts."; RL Mol. Biol. Cell 7:129-142(1996). RN [2] RP NUCLEOTIDE SEQUENCE [MRNA]. RC STRAIN=BALB/cJ; TISSUE=Brain; RA Westberg M.S., Lundberg L.G.; RT "Antisense technology and bone resorption."; RL Submitted (APR-1997) to the EMBL/GenBank/DDBJ databases. RN [3] RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA]. RC STRAIN=C57BL/6J; TISSUE=Amnion, Bone marrow, Brain, and Heart; RX PubMed=16141072; DOI=10.1126/science.1112014; RA Carninci P., Kasukawa T., Katayama S., Gough J., Frith M.C., Maeda N., RA Oyama R., Ravasi T., Lenhard B., Wells C., Kodzius R., Shimokawa K., RA Bajic V.B., Brenner S.E., Batalov S., Forrest A.R., Zavolan M., Davis M.J., RA Wilming L.G., Aidinis V., Allen J.E., Ambesi-Impiombato A., Apweiler R., RA Aturaliya R.N., Bailey T.L., Bansal M., Baxter L., Beisel K.W., Bersano T., RA Bono H., Chalk A.M., Chiu K.P., Choudhary V., Christoffels A., RA Clutterbuck D.R., Crowe M.L., Dalla E., Dalrymple B.P., de Bono B., RA Della Gatta G., di Bernardo D., Down T., Engstrom P., Fagiolini M., RA Faulkner G., Fletcher C.F., Fukushima T., Furuno M., Futaki S., RA Gariboldi M., Georgii-Hemming P., Gingeras T.R., Gojobori T., Green R.E., RA Gustincich S., Harbers M., Hayashi Y., Hensch T.K., Hirokawa N., Hill D., RA Huminiecki L., Iacono M., Ikeo K., Iwama A., Ishikawa T., Jakt M., RA Kanapin A., Katoh M., Kawasawa Y., Kelso J., Kitamura H., Kitano H., RA Kollias G., Krishnan S.P., Kruger A., Kummerfeld S.K., Kurochkin I.V., RA Lareau L.F., Lazarevic D., Lipovich L., Liu J., Liuni S., McWilliam S., RA Madan Babu M., Madera M., Marchionni L., Matsuda H., Matsuzawa S., Miki H., RA Mignone F., Miyake S., Morris K., Mottagui-Tabar S., Mulder N., Nakano N., RA Nakauchi H., Ng P., Nilsson R., Nishiguchi S., Nishikawa S., Nori F., RA Ohara O., Okazaki Y., Orlando V., Pang K.C., Pavan W.J., Pavesi G., RA Pesole G., Petrovsky N., Piazza S., Reed J., Reid J.F., Ring B.Z., RA Ringwald M., Rost B., Ruan Y., Salzberg S.L., Sandelin A., Schneider C., RA Schoenbach C., Sekiguchi K., Semple C.A., Seno S., Sessa L., Sheng Y., RA Shibata Y., Shimada H., Shimada K., Silva D., Sinclair B., Sperling S., RA Stupka E., Sugiura K., Sultana R., Takenaka Y., Taki K., Tammoja K., RA Tan S.L., Tang S., Taylor M.S., Tegner J., Teichmann S.A., Ueda H.R., RA van Nimwegen E., Verardo R., Wei C.L., Yagi K., Yamanishi H., RA Zabarovsky E., Zhu S., Zimmer A., Hide W., Bult C., Grimmond S.M., RA Teasdale R.D., Liu E.T., Brusic V., Quackenbush J., Wahlestedt C., RA Mattick J.S., Hume D.A., Kai C., Sasaki D., Tomaru Y., Fukuda S., RA Kanamori-Katayama M., Suzuki M., Aoki J., Arakawa T., Iida J., Imamura K., RA Itoh M., Kato T., Kawaji H., Kawagashira N., Kawashima T., Kojima M., RA Kondo S., Konno H., Nakano K., Ninomiya N., Nishio T., Okada M., Plessy C., RA Shibata K., Shiraki T., Suzuki S., Tagami M., Waki K., Watahiki A., RA Okamura-Oho Y., Suzuki H., Kawai J., Hayashizaki Y.; RT "The transcriptional landscape of the mammalian genome."; RL Science 309:1559-1563(2005). RN [4] RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA]. RC TISSUE=Eye, and Olfactory epithelium; RX PubMed=15489334; DOI=10.1101/gr.2596504; RG The MGC Project Team; RT "The status, quality, and expansion of the NIH full-length cDNA project: RT the Mammalian Gene Collection (MGC)."; RL Genome Res. 14:2121-2127(2004). RN [5] RP PROTEIN SEQUENCE OF 49-64; 68-130; 164-185; 189-208; 277-308; 322-337; RP 387-400; 404-430; 437-457; 461-485 AND 495-506, AND IDENTIFICATION BY MASS RP SPECTROMETRY. RC STRAIN=C57BL/6J, and OF1; TISSUE=Brain, and Hippocampus; RA Lubec G., Klug S., Yang J.W., Zigmond M., Kang S.U., Sunyer B., Chen W.-Q.; RL Submitted (JAN-2009) to UniProtKB. RN [6] RP SUBCELLULAR LOCATION, AND TISSUE SPECIFICITY. RX PubMed=15013950; DOI=10.1152/ajpcell.00464.2003; RA Paunescu T.G., Da Silva N., Marshansky V., McKee M., Breton S., Brown D.; RT "Expression of the 56-kDa B2 subunit isoform of the vacuolar H(+)-ATPase in RT proton-secreting cells of the kidney and epididymis."; RL Am. J. Physiol. 287:C149-C162(2004). RN [7] RP SUBCELLULAR LOCATION, AND TISSUE SPECIFICITY. RX PubMed=16174750; DOI=10.1073/pnas.0506769102; RA Finberg K.E., Wagner C.A., Bailey M.A., Paunescu T.G., Breton S., Brown D., RA Giebisch G., Geibel J.P., Lifton R.P.; RT "The B1-subunit of the H(+) ATPase is required for maximal urinary RT acidification."; RL Proc. Natl. Acad. Sci. U.S.A. 102:13616-13621(2005). RN [8] RP FUNCTION, SUBCELLULAR LOCATION, AND TISSUE SPECIFICITY. RX PubMed=17898041; DOI=10.1152/ajprenal.00160.2007; RA Paunescu T.G., Russo L.M., Da Silva N., Kovacikova J., Mohebbi N., RA Van Hoek A.N., McKee M., Wagner C.A., Breton S., Brown D.; RT "Compensatory membrane expression of the V-ATPase B2 subunit isoform in RT renal medullary intercalated cells of B1-deficient mice."; RL Am. J. Physiol. 293:F1915-F1926(2007). RN [9] RP IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS]. RC TISSUE=Brain, Brown adipose tissue, Heart, Kidney, Liver, Lung, RC Pancreas, Spleen, and Testis; RX PubMed=21183079; DOI=10.1016/j.cell.2010.12.001; RA Huttlin E.L., Jedrychowski M.P., Elias J.E., Goswami T., Rad R., RA Beausoleil S.A., Villen J., Haas W., Sowa M.E., Gygi S.P.; RT "A tissue-specific atlas of mouse protein phosphorylation and expression."; RL Cell 143:1174-1189(2010). RN [10] RP DISRUPTION PHENOTYPE, AND TISSUE SPECIFICITY. RX PubMed=24913193; DOI=10.1038/cr.2014.77; RA Yuan Y., Zhang J., Chang Q., Zeng J., Xin F., Wang J., Zhu Q., Wu J., RA Lu J., Guo W., Yan X., Jiang H., Zhou B., Li Q., Gao X., Yuan H., Yang S., RA Han D., Mao Z., Chen P., Lin X., Dai P.; RT "De novo mutation in ATP6V1B2 impairs lysosome acidification and causes RT dominant deafness-onychodystrophy syndrome."; RL Cell Res. 24:1370-1373(2014). RN [11] RP SUBCELLULAR LOCATION, AND TISSUE SPECIFICITY. RX PubMed=29993276; DOI=10.1152/ajprenal.00539.2017; RA Frische S., Chambrey R., Trepiccione F., Zamani R., Marcussen N., RA Alexander R.T., Skjoedt K., Svenningsen P., Dimke H.; RT "H+-ATPase B1 subunit localizes to thick ascending limb and distal RT convoluted tubule of rodent and human kidney."; RL Am. J. Physiol. 315:F429-F444(2018). CC -!- FUNCTION: Non-catalytic subunit of the V1 complex of vacuolar(H+)- CC ATPase (V-ATPase), a multisubunit enzyme composed of a peripheral CC complex (V1) that hydrolyzes ATP and a membrane integral complex (V0) CC that translocates protons (PubMed:17898041). V-ATPase is responsible CC for acidifying and maintaining the pH of intracellular compartments and CC in some cell types, is targeted to the plasma membrane, where it is CC responsible for acidifying the extracellular environment (By CC similarity). In renal intercalated cells, can partially compensate the CC lack of ATP6V1B1 and mediate secretion of protons (H+) into the urine CC under base-line conditions but not in conditions of acid load CC (PubMed:17898041). {ECO:0000250|UniProtKB:P21281, CC ECO:0000269|PubMed:17898041}. CC -!- SUBUNIT: V-ATPase is a heteromultimeric enzyme made up of two CC complexes: the ATP-hydrolytic V1 complex and the proton translocation CC V0 complex (By similarity). The V1 complex consists of three catalytic CC AB heterodimers that form a heterohexamer, three peripheral stalks each CC consisting of EG heterodimers, one central rotor including subunits D CC and F, and the regulatory subunits C and H (By similarity). The proton CC translocation complex V0 consists of the proton transport subunit a, a CC ring of proteolipid subunits c9c'', rotary subunit d, subunits e and f, CC and the accessory subunits ATP6AP1/Ac45 and ATP6AP2/PRR (By CC similarity). {ECO:0000250|UniProtKB:P21281}. CC -!- SUBCELLULAR LOCATION: Apical cell membrane CC {ECO:0000269|PubMed:15013950, ECO:0000269|PubMed:16174750, CC ECO:0000269|PubMed:17898041, ECO:0000269|PubMed:29993276}. Melanosome CC {ECO:0000250|UniProtKB:P21281}. Cytoplasm {ECO:0000269|PubMed:15013950, CC ECO:0000269|PubMed:17898041}. Cytoplasmic vesicle, secretory vesicle, CC synaptic vesicle membrane {ECO:0000250|UniProtKB:P62815}; Peripheral CC membrane protein {ECO:0000305}. Cytoplasmic vesicle, clathrin-coated CC vesicle membrane {ECO:0000250|UniProtKB:P62815}; Peripheral membrane CC protein {ECO:0000305}. CC -!- TISSUE SPECIFICITY: Kidney; found in early distal nephron, encompassing CC thick ascending limbs and distal convoluted tubules and in the alpha- CC intercalated cells of the cortical collecting ducts (at protein level) CC (PubMed:16174750, PubMed:29993276, PubMed:17898041, PubMed:15013950). CC Expressed in epididymal clear cells (at protein level) CC (PubMed:15013950). Mainly expressed in the organ of Corti and spiral CC ganglion neurons, in both the early postnatal cochlea (P2) and the CC adult cochlea (P30) (PubMed:24913193). {ECO:0000269|PubMed:15013950, CC ECO:0000269|PubMed:16174750, ECO:0000269|PubMed:17898041, CC ECO:0000269|PubMed:24913193, ECO:0000269|PubMed:29993276}. CC -!- DISRUPTION PHENOTYPE: Morpholino knockdown in the whole cochlea, CC especially in hair cells and spiral ganglion neurons causes a dose- CC dependent hearing loss. {ECO:0000269|PubMed:24913193}. CC -!- SIMILARITY: Belongs to the ATPase alpha/beta chains family. CC {ECO:0000305}. CC -!- SEQUENCE CAUTION: CC Sequence=BAE30303.1; Type=Erroneous initiation; Evidence={ECO:0000305}; CC Sequence=BAE30526.1; Type=Erroneous initiation; Evidence={ECO:0000305}; CC Sequence=BAE31441.1; Type=Erroneous initiation; Evidence={ECO:0000305}; CC --------------------------------------------------------------------------- CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms CC Distributed under the Creative Commons Attribution (CC BY 4.0) License CC --------------------------------------------------------------------------- DR EMBL; U13838; AAC52411.1; -; Genomic_DNA. DR EMBL; Y12634; CAA73182.1; -; mRNA. DR EMBL; AK146499; BAE27215.1; -; mRNA. DR EMBL; AK151200; BAE30197.1; -; mRNA. DR EMBL; AK151322; BAE30303.1; ALT_INIT; mRNA. DR EMBL; AK151586; BAE30526.1; ALT_INIT; mRNA. DR EMBL; AK152718; BAE31441.1; ALT_INIT; mRNA. DR EMBL; AK152766; BAE31479.1; -; mRNA. DR EMBL; AK159133; BAE34845.1; -; mRNA. DR EMBL; AK159153; BAE34860.1; -; mRNA. DR EMBL; AK159586; BAE35206.1; -; mRNA. DR EMBL; AK159701; BAE35300.1; -; mRNA. DR EMBL; AK159986; BAE35536.1; -; mRNA. DR EMBL; AK160080; BAE35612.1; -; mRNA. DR EMBL; AK160854; BAE36047.1; -; mRNA. DR EMBL; AK166669; BAE38930.1; -; mRNA. DR EMBL; AK168852; BAE40674.1; -; mRNA. DR EMBL; AK169155; BAE40934.1; -; mRNA. DR EMBL; AK169270; BAE41031.1; -; mRNA. DR EMBL; BC012497; AAH12497.1; -; mRNA. DR EMBL; BC046302; AAH46302.1; -; mRNA. DR EMBL; BC085300; AAH85300.1; -; mRNA. DR CCDS; CCDS40358.1; -. DR RefSeq; NP_031535.2; NM_007509.3. DR AlphaFoldDB; P62814; -. DR SMR; P62814; -. DR BioGRID; 198262; 25. DR IntAct; P62814; 8. DR MINT; P62814; -. DR STRING; 10090.ENSMUSP00000006435; -. DR TCDB; 3.A.2.2.6; the h+- or na+-translocating f-type, v-type and a-type atpase (f-atpase) superfamily. DR GlyGen; P62814; 1 site, 1 O-linked glycan (1 site). DR iPTMnet; P62814; -. DR MetOSite; P62814; -. DR PhosphoSitePlus; P62814; -. DR SwissPalm; P62814; -. DR REPRODUCTION-2DPAGE; P62814; -. DR EPD; P62814; -. DR jPOST; P62814; -. DR MaxQB; P62814; -. DR PaxDb; 10090-ENSMUSP00000006435; -. DR PeptideAtlas; P62814; -. DR ProteomicsDB; 297957; -. DR Pumba; P62814; -. DR Antibodypedia; 9185; 284 antibodies from 31 providers. DR DNASU; 11966; -. DR Ensembl; ENSMUST00000006435.8; ENSMUSP00000006435.8; ENSMUSG00000006273.15. DR GeneID; 11966; -. DR KEGG; mmu:11966; -. DR UCSC; uc009lww.2; mouse. DR AGR; MGI:109618; -. DR CTD; 526; -. DR MGI; MGI:109618; Atp6v1b2. DR VEuPathDB; HostDB:ENSMUSG00000006273; -. DR eggNOG; KOG1351; Eukaryota. DR GeneTree; ENSGT00940000155068; -. DR HOGENOM; CLU_022916_3_0_1; -. DR InParanoid; P62814; -. DR OMA; GFKIKPR; -. DR OrthoDB; 5473721at2759; -. DR PhylomeDB; P62814; -. DR TreeFam; TF300313; -. DR Reactome; R-MMU-1222556; ROS and RNS production in phagocytes. DR Reactome; R-MMU-77387; Insulin receptor recycling. DR Reactome; R-MMU-917977; Transferrin endocytosis and recycling. DR Reactome; R-MMU-9639288; Amino acids regulate mTORC1. DR Reactome; R-MMU-983712; Ion channel transport. DR BioGRID-ORCS; 11966; 28 hits in 79 CRISPR screens. DR ChiTaRS; Atp6v1b2; mouse. DR PRO; PR:P62814; -. DR Proteomes; UP000000589; Chromosome 8. DR RNAct; P62814; Protein. DR Bgee; ENSMUSG00000006273; Expressed in pontine nuclear group and 274 other cell types or tissues. DR GO; GO:0016324; C:apical plasma membrane; IDA:UniProtKB. DR GO; GO:0030665; C:clathrin-coated vesicle membrane; IEA:UniProtKB-SubCell. DR GO; GO:0005737; C:cytoplasm; IDA:UniProtKB. DR GO; GO:0005829; C:cytosol; IDA:UniProtKB. DR GO; GO:0098850; C:extrinsic component of synaptic vesicle membrane; ISO:MGI. DR GO; GO:0043231; C:intracellular membrane-bounded organelle; ISO:MGI. DR GO; GO:0042470; C:melanosome; IEA:UniProtKB-SubCell. DR GO; GO:0005902; C:microvillus; IDA:UniProtKB. DR GO; GO:0043209; C:myelin sheath; HDA:UniProtKB. DR GO; GO:0005886; C:plasma membrane; IDA:UniProtKB. DR GO; GO:0001726; C:ruffle; IDA:UniProtKB. DR GO; GO:0000221; C:vacuolar proton-transporting V-type ATPase, V1 domain; ISS:UniProtKB. DR GO; GO:0005524; F:ATP binding; IEA:UniProtKB-KW. DR GO; GO:0046961; F:proton-transporting ATPase activity, rotational mechanism; IBA:GO_Central. DR GO; GO:0046034; P:ATP metabolic process; IEA:InterPro. DR GO; GO:0097401; P:synaptic vesicle lumen acidification; IDA:SynGO. DR GO; GO:0007035; P:vacuolar acidification; IBA:GO_Central. DR CDD; cd18112; ATP-synt_V_A-type_beta_C; 1. DR CDD; cd18118; ATP-synt_V_A-type_beta_N; 1. DR CDD; cd01135; V_A-ATPase_B; 1. DR Gene3D; 3.40.50.12240; -; 1. DR HAMAP; MF_00310; ATP_synth_B_arch; 1. DR InterPro; IPR020003; ATPase_a/bsu_AS. DR InterPro; IPR004100; ATPase_F1/V1/A1_a/bsu_N. DR InterPro; IPR000194; ATPase_F1/V1/A1_a/bsu_nucl-bd. DR InterPro; IPR005723; ATPase_V1-cplx_bsu. DR InterPro; IPR027417; P-loop_NTPase. DR InterPro; IPR022879; V-ATPase_su_B/beta. DR NCBIfam; TIGR01040; V-ATPase_V1_B; 1. DR PANTHER; PTHR43389; V-TYPE PROTON ATPASE SUBUNIT B; 1. DR PANTHER; PTHR43389:SF5; V-TYPE PROTON ATPASE SUBUNIT B, BRAIN ISOFORM; 1. DR Pfam; PF00006; ATP-synt_ab; 1. DR Pfam; PF02874; ATP-synt_ab_N; 1. DR PIRSF; PIRSF039114; V-ATPsynth_beta/V-ATPase_B; 1. DR SUPFAM; SSF52540; P-loop containing nucleoside triphosphate hydrolases; 1. DR PROSITE; PS00152; ATPASE_ALPHA_BETA; 1. DR UCD-2DPAGE; P62814; -. DR Genevisible; P62814; MM. PE 1: Evidence at protein level; KW ATP-binding; Cell membrane; Cytoplasm; Cytoplasmic vesicle; KW Direct protein sequencing; Hydrogen ion transport; Ion transport; Membrane; KW Nucleotide-binding; Reference proteome; Synapse; Transport. FT CHAIN 1..511 FT /note="V-type proton ATPase subunit B, brain isoform" FT /id="PRO_0000144627" FT BINDING 400 FT /ligand="ATP" FT /ligand_id="ChEBI:CHEBI:30616" FT /evidence="ECO:0000250|UniProtKB:P21281" FT CONFLICT 22..23 FT /note="GG -> RP (in Ref. 1; AAC52411)" FT /evidence="ECO:0000305" FT CONFLICT 36 FT /note="S -> G (in Ref. 1; AAC52411)" FT /evidence="ECO:0000305" FT CONFLICT 80 FT /note="T -> A (in Ref. 3; BAE35206)" FT /evidence="ECO:0000305" FT CONFLICT 85..86 FT /note="QV -> AS (in Ref. 1; AAC52411)" FT /evidence="ECO:0000305" FT CONFLICT 262..264 FT /note="NLA -> ILP (in Ref. 1; AAC52411)" FT /evidence="ECO:0000305" FT CONFLICT 270 FT /note="E -> K (in Ref. 3; BAE35536/BAE35612)" FT /evidence="ECO:0000305" FT CONFLICT 276 FT /note="R -> C (in Ref. 1; AAC52411)" FT /evidence="ECO:0000305" FT CONFLICT 300 FT /note="M -> T (in Ref. 1; AAC52411)" FT /evidence="ECO:0000305" FT CONFLICT 304 FT /note="A -> P (in Ref. 1; AAC52411)" FT /evidence="ECO:0000305" FT CONFLICT 318 FT /note="P -> H (in Ref. 3; BAE35536/BAE35612)" FT /evidence="ECO:0000305" FT CONFLICT 365 FT /note="I -> M (in Ref. 3; BAE40674)" FT /evidence="ECO:0000305" FT CONFLICT 371 FT /note="Y -> C (in Ref. 3; BAE35206)" FT /evidence="ECO:0000305" FT CONFLICT 373 FT /note="T -> I (in Ref. 3; BAE30303/BAE30526)" FT /evidence="ECO:0000305" FT CONFLICT 405 FT /note="A -> P (in Ref. 1; AAC52411)" FT /evidence="ECO:0000305" FT CONFLICT 437 FT /note="A -> V (in Ref. 3; BAE30197)" FT /evidence="ECO:0000305" SQ SEQUENCE 511 AA; 56551 MW; E116BF9A36EEF36B CRC64; MALRAMRGIV NGAAPELPVP TGGPMAGARE QALAVSRNYL SQPRLTYKTV SGVNGPLVIL DHVKFPRYAE IVHLTLPDGT KRSGQVLEVS GSKAVVQVFE GTSGIDAKKT SCEFTGDILR TPVSEDMLGR VFNGSGKPID RGPVVLAEDF LDIMGQPINP QCRIYPEEMI QTGISAIDGM NSIARGQKIP IFSAAGLPHN EIAAQICRQA GLVKKSKDVV DYSEENFAIV FAAMGVNMET ARFFKSDFEE NGSMDNVCLF LNLANDPTIE RIITPRLALT TAEFLAYQCE KHVLVILTDM SSYAEALREV SAAREEVPGR RGFPGYMYTD LATIYERAGR VEGRNGSITQ IPILTMPNDD ITHPIPDLTG YITEGQIYVD RQLHNRQIYP PINVLPSLSR LMKSAIGEGM TRKDHADVSN QLYACYAIGK DVQAMKAVVG EEALTSDDLL YLEFLQKFEK NFITQGPYEN RTVYETLDIG WQLLRIFPKE MLKRIPQSTL SEFYPRDSAK H //