AK6

Summary

AK6 (adenylate kinase 6, HGNC:49151) is a protein-coding gene on chromosome 5q13.2, encoding Adenylate kinase isoenzyme 6 (Q9Y3D8). Broad-specificity nucleoside monophosphate (NMP) kinase that catalyzes the reversible transfer of the terminal phosphate group between nucleoside triphosphates and monophosphates.

This gene encodes a protein that belongs to the adenylate kinase family of enzymes. The protein has a nuclear localization and contains Walker A (P-loop) and Walker B motifs and a metal-coordinating residue. The protein may be involved in regulation of Cajal body formation. In human, AK6 and TAF9 (GeneID: 6880) are two distinct genes that share 5’ exons. Alternative splicing results in multiple transcript variants.

Source: NCBI Gene 102157402 — RefSeq curated summary.

At a glance

• GWAS associations: 1
• Clinical variants (ClinVar): 36 total
• MANE Select transcript: NM_016283

Identifiers

Gene identifiers

Field	Value
HGNC ID	HGNC:49151
Approved symbol	AK6
Name	adenylate kinase 6
Location	5q13.2
Locus type	gene with protein product
Status	Approved
Aliases	CINAP
Ensembl gene	ENSG00000085231
Ensembl biotype	protein_coding
OMIM	619357
Entrez	102157402

Gene structure

Transcript identifiers

Ensembl transcripts: 5 — 5 protein_coding

ENST00000380818, ENST00000380822, ENST00000502819, ENST00000512561, ENST00000618980

RefSeq mRNA: 2 — MANE Select: NM_016283 NM_001015891, NM_016283

CCDS: CCDS4001, CCDS43324

Canonical transcript exons

ENST00000380822 — 5 exons

Exon	Start	End
ENSE00001486410	69355649	69355794
ENSE00001486415	69355895	69355953
ENSE00001549839	69350984	69352253
ENSE00002086906	69369463	69369520
ENSE00003719110	69366503	69366595

Expression profiles

Bgee: expression breadth ubiquitous, 134 present calls, max score 96.15.

FANTOM5 (CAGE): breadth ubiquitous, TPM avg 5.1618 / max 107.6608, expressed in 1602 samples.

FANTOM5 promoters (5 alternative TSS)

Promoter ID	TPM avg	Samples expressed
62019	60.0109	1817
62022	3.7826	1344
62021	0.6954	402
62020	0.6838	414
62023	0.1776	54

Top tissues by expression

134 total, by Bgee expression score (0-100, higher = more expressed):

Tissue	Anatomy ID	Expression score	Quality
calcaneal tendon	UBERON:0003701	96.15	gold quality
adrenal tissue	UBERON:0018303	95.89	gold quality
left adrenal gland	UBERON:0001234	95.87	gold quality
right adrenal gland	UBERON:0001233	95.80	gold quality
right adrenal gland cortex	UBERON:0035827	95.80	gold quality
male germ line stem cell (sensu Vertebrata) in testis	CL:0000089 ∩ UBERON:0000473	95.79	gold quality
left adrenal gland cortex	UBERON:0035825	95.72	gold quality
endometrium	UBERON:0001295	95.65	gold quality
hindlimb stylopod muscle	UBERON:0004252	95.61	gold quality
ventricular zone	UBERON:0003053	95.58	gold quality
gastrocnemius	UBERON:0001388	95.55	gold quality
mucosa of transverse colon	UBERON:0004991	95.42	gold quality
muscle of leg	UBERON:0001383	95.30	gold quality
adrenal gland	UBERON:0002369	95.28	gold quality
nucleus accumbens	UBERON:0001882	95.19	gold quality
right testis	UBERON:0004534	95.18	gold quality
caudate nucleus	UBERON:0001873	95.09	gold quality
islet of Langerhans	UBERON:0000006	95.08	gold quality
omental fat pad	UBERON:0010414	95.05	gold quality
left testis	UBERON:0004533	94.93	gold quality
testis	UBERON:0000473	94.89	gold quality
superior frontal gyrus	UBERON:0002661	94.83	gold quality
anterior cingulate cortex	UBERON:0009835	94.76	gold quality
tibial artery	UBERON:0007610	94.74	gold quality
popliteal artery	UBERON:0002250	94.73	gold quality
putamen	UBERON:0001874	94.68	gold quality
dorsolateral prefrontal cortex	UBERON:0009834	94.58	gold quality
left coronary artery	UBERON:0001626	94.50	gold quality
muscle layer of sigmoid colon	UBERON:0035805	94.50	gold quality
body of pancreas	UBERON:0001150	94.49	gold quality

Single-cell (SCXA)

Detected in 2 experiment(s), a significant marker in 2.

Experiment	Marker?	Max mean expression
E-CURD-112	yes	8.32
E-ANND-3	yes	7.51

Regulation

Is transcription factor: no

miRNA regulators (miRDB)

26 targeting AK6, top 30 by miRDB confidence (max_score; target_count = how many genes the miRNA targets in total — lower means more specific):

miRNA	Max score	Avg score	miRNA target_count
HSA-MIR-4531	99.99	69.70	3181
HSA-MIR-27A-3P	99.98	72.13	2955
HSA-MIR-27B-3P	99.98	72.13	2955
HSA-MIR-9985	99.98	72.11	2939
HSA-MIR-3065-5P	99.97	71.56	3281
HSA-MIR-3686	99.90	70.53	2432
HSA-MIR-8062	99.88	68.43	995
HSA-MIR-8084	99.73	69.57	1760
HSA-MIR-4516	99.61	67.78	3390
HSA-MIR-888-3P	99.53	69.77	1057
HSA-MIR-7159-3P	99.51	70.17	1920
HSA-MIR-20A-3P	99.44	69.10	1575
HSA-MIR-3160-5P	99.28	69.07	1938
HSA-MIR-664A-3P	99.22	71.08	2696
HSA-MIR-4528	99.18	69.77	1936
HSA-MIR-6074	98.89	69.64	2187
HSA-MIR-4477A	98.83	69.75	2952
HSA-MIR-4766-3P	98.48	67.94	1347
HSA-MIR-4772-3P	98.04	65.60	1203
HSA-MIR-6529-5P	97.85	66.47	673
HSA-MIR-144-5P	97.66	69.90	531
HSA-MIR-562	97.66	65.63	698
HSA-MIR-6730-3P	97.03	67.54	889
HSA-MIR-152-5P	96.42	66.59	960
HSA-MIR-5586-3P	95.51	67.00	805
HSA-MIR-4765	93.11	66.17	737

Literature-anchored findings (GeneRIF, showing 8)

• purification and X ray crystal structure (PMID:15213396)
• hCINAP is a novel coilin-interacting protein encoded by a transcript from the transcription factor TAFIID32 locus (PMID:16079131)
• hCINAP determines self-renewal of colorectal cancer stem cells by facilitating LDHA phosphorylation. (PMID:28516914)
• These results provide mechanistic insight into the function of hCINAP during the DNA-damage response and its role in acute myelocytic leukemia resistance to therapy. (PMID:31444354)
• The mRNA and protein expressions of AK1, AK6 and AK7 are significantly down-regulated in the sperm of asthenospermia patients, which may be closely related with reduced sperm motility. (PMID:32251557)
• hCINAP is potentially a direct target gene of HIF-1 and is required for hypoxia-induced EMT and apoptosis in cervical cancer cells. (PMID:32830518)
• Human adenylate kinase 6 regulates WNK1 (with no lysine kinase-1) phosphorylation states and affects ion homeostasis in NT2 cells. (PMID:33744230)
• Unique structural features of the adenylate kinase hCINAP/AK6 and its multifaceted functions in carcinogenesis and tumor progression. (PMID:34245011)

Cross-species orthologs

5 orthologs

Organism	Symbol	Gene ID
danio_rerio	AK6	ENSDARG00000035573
rattus_norvegicus	Ak6	ENSRNOG00000026813
rattus_norvegicus	Ak6	ENSRNOG00000063018
drosophila_melanogaster	Ak6	FBGN0033754
caenorhabditis_elegans		WBGENE00008458

Protein

Protein identifiers

Adenylate kinase isoenzyme 6 — Q9Y3D8 (reviewed: Q9Y3D8)

Alternative names: Adrenal gland protein AD-004, Coilin-interacting nuclear ATPase protein, Dual activity adenylate kinase/ATPase

All UniProt accessions (5): Q9Y3D8, A0A087WVD7, A0A087WY94, A0AAU7BBC0, D6RDH4

UniProt curated annotations — full annotation on UniProt →

Function. Broad-specificity nucleoside monophosphate (NMP) kinase that catalyzes the reversible transfer of the terminal phosphate group between nucleoside triphosphates and monophosphates. Also has ATPase activity. Involved in the late cytoplasmic maturation steps of the 40S ribosomal particles, specifically 18S rRNA maturation. While NMP activity is not required for ribosome maturation, ATPase activity is. Associates transiently with small ribosomal subunit protein uS11. ATP hydrolysis breaks the interaction with uS11. May temporarily remove uS11 from the ribosome to enable a conformational change of the ribosomal RNA that is needed for the final maturation step of the small ribosomal subunit. Its NMP activity may have a role in nuclear energy homeostasis. AMP and dAMP are the preferred substrates, but CMP and dCMP are also good substrates. IMP is phosphorylated to a much lesser extent. All nucleoside triphosphates ATP, GTP, UTP, CTP, dATP, dCTP, dGTP, and TTP are accepted as phosphate donors. CTP is the best phosphate donor, followed by UTP, ATP, GTP and dCTP. May be involved in regulation of Cajal body (CB) formation.

Subunit / interactions. Monomer and homodimer. Interacts with small ribosomal subunit protein uS11. Not a structural component of 43S pre-ribosomes, but transiently interacts with them by binding to uS11. Interacts with COIL (via C-terminus).

Subcellular location. Cytoplasm. Nucleus. Nucleoplasm. Cajal body.

Tissue specificity. Expressed in heart, brain, placenta, lung, liver, skeletal muscle, kidney, pancreas, chorionic villi and the central nervous system.

Similarity. Belongs to the adenylate kinase family. AK6 subfamily.

Isoforms (2)

UniProt ID	Names	Canonical?
Q9Y3D8-1	1, AK6	yes
Q9Y3D8-2	2

RefSeq proteins (2): NP_001015891, NP_057367* (*=MANE)

Domains & families (InterPro)

ID	Name	Type
IPR020618	Adenyl_kinase_AK6	Family
IPR027417	P-loop_NTPase	Homologous_superfamily

Pfam: PF13238

Enzyme classification (BRENDA):

• EC 2.7.4.3 — adenylate kinase (BRENDA: 73 organisms, 259 substrates, 134 inhibitors, 192 Km, 47 kcat entries)

Substrate kinetics (BRENDA)

9 substrates with measured Km, best-characterized 9. Km ranges are aggregated across organisms/conditions.

Substrate	Km (mM)	Measurements
AMP	0.0014–1.9	59
ATP	0.0001–7	58
ADP	0.003–16.8	27
2 ADP	0.006–0.15	5
DAMP	0.507–2	2
2’-DAMP	0.85	1
7-DEAZAADENOSINE 5’-MONOPHOSPHATE	0.73	1
ADP3-	0.03	1
CMP	0.0002	1

Catalyzed reactions (Rhea), 2 shown:

• AMP + ATP = 2 ADP (RHEA:12973)
• ATP + H2O = ADP + phosphate + H(+) (RHEA:13065)

UniProt features (30 total): helix 9, binding site 7, strand 7, region of interest 3, chain 1, splice variant 1, mutagenesis site 1, turn 1

Structure

Experimental structures (PDB)

6 structures.

PDB	Method	Resolution (Å)
3IIJ	X-RAY DIFFRACTION	1.76
3IIK	X-RAY DIFFRACTION	1.95
1RKB	X-RAY DIFFRACTION	2
3IIL	X-RAY DIFFRACTION	2
3IIM	X-RAY DIFFRACTION	2
5JZV	X-RAY DIFFRACTION	2.07

Predicted structure (AlphaFold)

Model	pLDDT	Fraction very-high
AF-Q9Y3D8-F1	97.15	0.97

Functional residue map

Curated UniProt residues grouped by drug-discovery relevance — catalytic, ligand-binding, modification, and mutation-validated positions. Source: UniProtKB sequence features.

Ligand- & substrate-binding residues (7): 148; 13; 15; 16; 17; 18; 109

Mutagenesis-validated functional residues (1):

Position	Phenotype
79	induces homodimerization. reduces adenylate kinase activity by 72% and atpase activity by 76%. significantly changes caj

Function

Pathways and Gene Ontology

Reactome pathways

3 pathways

ID	Pathway
R-HSA-499943	Interconversion of nucleotide di- and triphosphates
R-HSA-1430728	Metabolism
R-HSA-15869	Metabolism of nucleotides

MSigDB gene sets: 92 (showing top): GOBP_RIBOSOME_BIOGENESIS, RODRIGUES_THYROID_CARCINOMA_POORLY_DIFFERENTIATED_UP, GOBP_ORGANOPHOSPHATE_METABOLIC_PROCESS, GOBP_NUCLEOSIDE_PHOSPHATE_BIOSYNTHETIC_PROCESS, GOBP_ORGANOPHOSPHATE_BIOSYNTHETIC_PROCESS, GOBP_NUCLEOBASE_CONTAINING_SMALL_MOLECULE_METABOLIC_PROCESS, MILI_PSEUDOPODIA_HAPTOTAXIS_UP, GOBP_RIBOSOMAL_SMALL_SUBUNIT_BIOGENESIS, GOBP_NUCLEOBASE_CONTAINING_SMALL_MOLECULE_INTERCONVERSION, GOBP_NUCLEOSIDE_MONOPHOSPHATE_METABOLIC_PROCESS, GOBP_RIBONUCLEOPROTEIN_COMPLEX_BIOGENESIS, GOCC_NUCLEAR_SPECK, GOCC_CAJAL_BODY, GOCC_NUCLEAR_BODY, GOCC_RIBONUCLEOPROTEIN_GRANULE

GO Biological Process (5): rRNA processing (GO:0006364), nucleobase-containing small molecule interconversion (GO:0015949), ribosomal small subunit biogenesis (GO:0042274), ribosome biogenesis (GO:0042254), nucleoside monophosphate phosphorylation (GO:0046940)

GO Molecular Function (8): AMP kinase activity (GO:0004017), ATP binding (GO:0005524), ATP hydrolysis activity (GO:0016887), nucleoside monophosphate kinase activity (GO:0050145), nucleotide binding (GO:0000166), protein binding (GO:0005515), kinase activity (GO:0016301), transferase activity (GO:0016740)

GO Cellular Component (7): nucleus (GO:0005634), nucleoplasm (GO:0005654), cytoplasm (GO:0005737), centrosome (GO:0005813), Cajal body (GO:0015030), membrane (GO:0016020), nuclear speck (GO:0016607)

Reactome top-level categories

Rollup of top-2 pathways:

Category	Pathways
Metabolism of nucleotides	1
Metabolism	1

GO top-level categories

Rollup of top GO terms by namespace:

Category	Terms
cellular anatomical structure	3
ribosome biogenesis	2
ribonucleoprotein complex biogenesis	2
nuclear ribonucleoprotein granule	2
RNA processing	1
rRNA metabolic process	1
nucleobase-containing small molecule metabolic process	1
nucleoside monophosphate metabolic process	1
nucleotide biosynthetic process	1
nucleoside monophosphate kinase activity	1
adenyl ribonucleotide binding	1
purine ribonucleoside triphosphate binding	1
ribonucleoside triphosphate phosphatase activity	1
ATP-dependent activity	1
phosphotransferase activity, phosphate group as acceptor	1
nucleobase-containing compound kinase activity	1
nucleoside phosphate binding	1
heterocyclic compound binding	1
binding	1
transferase activity, transferring phosphorus-containing groups	1
catalytic activity	1
intracellular membrane-bounded organelle	1
nuclear lumen	1
intracellular anatomical structure	1
centriole	1
microtubule organizing center	1

Protein interactions and networks

STRING

1252 interactions, top by confidence (×1000):

Protein A	Protein B	Partner UniProt	Score
AK6	COIL	P38432	661
AK6	NOB1	Q9ULX3	607
AK6	SENP8	Q96LD8	605
AK6	AK9	Q5TCS8	593
AK6	RPS14	P06366	565
AK6	AK5	Q9Y6K8	528
AK6	RIOK2	Q9BVS4	491
AK6	RIOK1	Q9BRS2	475
AK6	AK8	Q96MA6	470
AK6	AK1	P00568	460
AK6	ENPP4	Q9Y6X5	450
AK6	QTRT1	Q9BXR0	447
AK6	AK2	P54819	433
AK6	LTV1	Q96GA3	404
AK6	AK7	Q96M32	399
AK6	TSR1	Q2NL82	399

IntAct

40 interactions, top by confidence:

A	B	Type	Score
AK6	RPS14	psi-mi:“MI:0915”(physical association)	0.740
RPS14	AK6	psi-mi:“MI:0915”(physical association)	0.740
TADA1	TAF5L	psi-mi:“MI:0914”(association)	0.640
RPS14	CCZ1B	psi-mi:“MI:0914”(association)	0.640
COIL	AK6	psi-mi:“MI:0915”(physical association)	0.600
AK6	COIL	psi-mi:“MI:0403”(colocalization)	0.600
AK6	COIL	psi-mi:“MI:0915”(physical association)	0.600
AK6	NDRG1	psi-mi:“MI:0915”(physical association)	0.560
LAMTOR5	AK6	psi-mi:“MI:0915”(physical association)	0.560
AK6	LAMTOR5	psi-mi:“MI:0915”(physical association)	0.560
TAF8	TAF4	psi-mi:“MI:0914”(association)	0.530
TADA2B	SUPT3H	psi-mi:“MI:0914”(association)	0.530
LPAR1	TMEM223	psi-mi:“MI:0914”(association)	0.530
TMEM63A	AP3D1	psi-mi:“MI:0914”(association)	0.530
FBLN1	AK6	psi-mi:“MI:0915”(physical association)	0.370
AK6	GALNT6	psi-mi:“MI:0915”(physical association)	0.370
	ZW10	psi-mi:“MI:0914”(association)	0.350
UNC93B1		psi-mi:“MI:0914”(association)	0.350
LRRK2		psi-mi:“MI:0914”(association)	0.350
ATXN7L3	USP27X	psi-mi:“MI:0914”(association)	0.350
TAF7L	TAF4	psi-mi:“MI:0914”(association)	0.350
MYCL	CASK	psi-mi:“MI:0914”(association)	0.350
TFEB	TFEC	psi-mi:“MI:0914”(association)	0.350

BioGRID (30): AK6 (Affinity Capture-MS), AK6 (Affinity Capture-MS), AK6 (Affinity Capture-MS), AK6 (Affinity Capture-MS), AK6 (Affinity Capture-MS), AK6 (Affinity Capture-MS), AK6 (Synthetic Lethality), AK6 (Affinity Capture-MS), AK6 (Affinity Capture-MS), AK6 (Affinity Capture-MS), AK6 (Affinity Capture-MS), AK6 (Negative Genetic), AK6 (Affinity Capture-MS), AK6 (Affinity Capture-MS), AK6 (Proximity Label-MS)

ESM2 similar proteins: A1L1L6, A5PJA1, B9N1F9, B9SQI7, E0CSI1, O43929, O80526, O95045, P08760, P29411, Q05B63, Q28DS0, Q28I42, Q2HJF8, Q2QNG7, Q2QZ86, Q2R483, Q2YDI2, Q5BJZ6, Q5EB68, Q5M939, Q5R4J9, Q5R6Z7, Q5RDZ0, Q5ZID6, Q5ZKF6, Q5ZM73, Q6AY91, Q6N069, Q6NVC5, Q7SYN4, Q7Z4G4, Q80UM3, Q8GYA6, Q8IXI2, Q8JGT5, Q8RWF0, Q8VCP8, Q91W63, Q923S8

Diamond homologs: A4YIQ9, A5PJA1, A6VHC3, B0R4Q3, B6YUL3, C3MQV5, C3MWU3, C3N6L0, C3N6Z8, C3NGL3, C4KI81, C5A628, O27656, O28278, O58998, Q09527, Q12055, Q3IRT0, Q46FV0, Q58450, Q5EB68, Q5JG26, Q7JYV7, Q834S1, Q8PZ69, Q8TG40, Q8TJQ0, Q8TWH4, Q8U1S1, Q8VCP8, Q8ZU30, Q976L5, Q97ZW3, Q9FJI1, Q9HQS1, Q9TTU2, Q9UU88, Q9UZK4, Q9Y3D8, B0R683

SIGNOR signaling

0 interactions.

Enriched among interaction partners

Reactome pathways and GO biological processes over-represented among this gene’s 43 IntAct physical interaction partners (hypergeometric vs the genome-wide background, BH-FDR, gene-set size 15–500, ranked by fold). A functional readout of the neighbourhood — distinct from this gene’s own memberships above, and biased toward well-studied / hub proteins, so read it as themes rather than proof.

Reactome pathways:

Pathway	Partners	Fold	FDR
Chromatin organization	7	16.8×	2e-05
HATs acetylate histones	7	16.3×	2e-05
Chromatin modifying enzymes	7	14.9×	2e-05

GO biological processes:

GO term	Partners	Fold	FDR
regulation of DNA repair	8	53.9×	5e-10
regulation of RNA splicing	7	37.4×	1e-07

Disease & clinical

Clinical variants and AI predictions

ClinVar

36 variants total. Per-class counts are floors (≥ shown; pagination cap):

Classification	Count (floor)
Pathogenic	0
Likely pathogenic	0
Uncertain significance	30
Likely benign	0
Benign	0

Top pathogenic / likely-pathogenic (0)

SpliceAI

0 predictions. Top by Δscore:

AlphaMissense

1134 scored. Top likely-pathogenic:

Variant	Protein change	am_pathogenicity
5:69352186:C:G	A132P	0.997
5:69355658:A:G	L106P	0.997
5:69355748:A:T	V76D	0.997
5:69366577:T:A	K16I	0.997
5:69366578:T:G	K16Q	0.997
5:69369463:C:G	G10R	0.997
5:69355740:G:C	H79D	0.996
5:69366574:G:A	T17I	0.996
5:69355713:A:G	W88R	0.995
5:69355713:A:T	W88R	0.995
5:69369463:C:A	G10C	0.995
5:69352212:T:A	E123V	0.994
5:69355660:T:A	R105S	0.994
5:69355660:T:G	R105S	0.994
5:69366511:G:T	A38D	0.994
5:69366565:C:T	G20D	0.994
5:69366566:C:G	G20R	0.994
5:69366576:T:A	K16N	0.994
5:69366576:T:G	K16N	0.994
5:69366586:C:T	G13E	0.994
5:69366587:C:A	G13W	0.994
5:69352185:G:T	A132D	0.993
5:69355700:A:T	V92D	0.993
5:69355738:A:C	H79Q	0.993
5:69355738:A:T	H79Q	0.993
5:69355746:C:G	D77H	0.993
5:69366580:C:T	G15E	0.993
5:69366595:C:A	G10V	0.993
5:69366595:C:T	G10D	0.993
5:69369471:A:G	L7P	0.993

dbSNP variants (sampled 300 via entrez): RS1000028016 (5:69353901 C>T), RS1000101039 (5:69352446 C>G,T), RS1000138339 (5:69353298 C>T), RS1000489369 (5:69353565 G>C), RS1000544145 (5:69359222 C>T), RS1000620327 (5:69359542 GCC>G), RS1000750325 (5:69352621 C>T), RS1000831641 (5:69370747 G>T), RS1000973410 (5:69370684 T>G), RS1001053447 (5:69370924 T>C), RS1001206108 (5:69353979 C>T), RS1001289306 (5:69370536 C>T), RS1001530686 (5:69361396 C>G,T), RS1001573408 (5:69354164 T>C), RS1001867796 (5:69360257 T>C)

Disease associations

OMIM: gene MIM:619357 | disease phenotypes:

GenCC curated gene-disease

Mondo (0):

Orphanet (0):

HPO phenotypes

0 total (0 of 0 shown, HPO-id order):

GWAS associations

1 associations (top):

Study	Trait	p-value
GCST008058_305	Estimated glomerular filtration rate	4.000000e-11

Drugs & pharmacology

Drug and pharmacology data

Is drug target: no

PharmGKB: 1 entry (VIP=true, CPIC=false)

CTD chemical–gene interactions

8 total (human), top 8 by PubMed support.

Chemical	Actions (top 5)	PubMed papers
aristolochic acid I	increases expression	1
sulforaphane	increases expression	1
di-n-butylphosphoric acid	affects expression	1
Doxorubicin	increases expression	1
Ivermectin	decreases expression	1
Tobacco Smoke Pollution	increases expression	1
Aflatoxin M1	decreases expression	1
Acrylamide	increases expression	1

Clinical trials (associated diseases)

0 trials via MONDO — disease-level, not drug-specific.