LCMT1

gene
On this page

Also known as CGI-68PPMT1

Summary

LCMT1 (leucine carboxyl methyltransferase 1, HGNC:17557) is a protein-coding gene on chromosome 16p12.1, encoding Leucine carboxyl methyltransferase 1 (Q9UIC8). Methylates the carboxyl group of the C-terminal leucine residue of protein phosphatase 2A catalytic subunits to form alpha-leucine ester residues. It is a selective cancer dependency (DepMap: 31.1% of cell lines).

LCMT1 catalyzes the methylation of the carboxyl group of the C-terminal leucine residue (leu309) of the catalytic subunit of protein phosphatase-2A (PPP2CA; MIM 176915) (De Baere et al., 1999 [PubMed 10600115]).

Source: NCBI Gene 51451 — RefSeq curated summary.

At a glance

  • GWAS associations: 1
  • Clinical variants (ClinVar): 68 total
  • Cancer dependency (DepMap): dependent in 31.1% of screened cell lines
  • MANE Select transcript: NM_016309

Identifiers

Gene identifiers

FieldValue
HGNC IDHGNC:17557
Approved symbolLCMT1
Nameleucine carboxyl methyltransferase 1
Location16p12.1
Locus typegene with protein product
StatusApproved
AliasesCGI-68, PPMT1
Ensembl geneENSG00000205629
Ensembl biotypeprotein_coding
OMIM610286
Entrez51451

Gene structure

Transcript identifiers

Ensembl transcripts: 18 — 10 protein_coding, 3 nonsense_mediated_decay, 3 protein_coding_CDS_not_defined, 2 retained_intron

ENST00000380962, ENST00000380966, ENST00000399069, ENST00000564011, ENST00000570981, ENST00000572761, ENST00000572869, ENST00000573435, ENST00000574450, ENST00000575396, ENST00000576382, ENST00000576625, ENST00000577157, ENST00000892900, ENST00000918761, ENST00000918762, ENST00000918763, ENST00000949527

RefSeq mRNA: 2 — MANE Select: NM_016309 NM_001032391, NM_016309

CCDS: CCDS45445, CCDS45446

Canonical transcript exons

ENST00000399069 — 11 exons

ExonStartEnd
ENSE000014870122511174225111996
ENSE000034923172517493725175034
ENSE000035467352517071425170805
ENSE000035477272516459825164718
ENSE000035557312516110225161204
ENSE000035599562512847525128566
ENSE000035599642516911225169213
ENSE000035711322515155425151615
ENSE000036400172514017125140247
ENSE000036746882513240225132523
ENSE000036903102517800125178228

Expression profiles

Bgee: expression breadth ubiquitous, 285 present calls, max score 96.49.

FANTOM5 (CAGE): breadth ubiquitous, TPM avg 32.6911 / max 165.9154, expressed in 1817 samples.

FANTOM5 promoters (4 alternative TSS)

Promoter IDTPM avgSamples expressed
15326618.49021809
15326713.48361787
1532650.5800328
1532680.137365

Top tissues by expression

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

TissueAnatomy IDExpression scoreQuality
middle temporal gyrusUBERON:000277196.49gold quality
body of pancreasUBERON:000115095.22gold quality
prefrontal cortexUBERON:000045195.18gold quality
oocyteCL:000002394.98gold quality
nucleus accumbensUBERON:000188294.98gold quality
cortical plateUBERON:000534394.84gold quality
right frontal lobeUBERON:000281094.83gold quality
primordial germ cell in gonadCL:0000670 ∩ UBERON:000099194.80gold quality
ponsUBERON:000098894.70gold quality
Brodmann (1909) area 23UBERON:001355494.65gold quality
anterior cingulate cortexUBERON:000983594.63gold quality
cingulate cortexUBERON:000302794.60gold quality
dorsolateral prefrontal cortexUBERON:000983494.51gold quality
Brodmann (1909) area 9UBERON:001354094.45gold quality
hindlimb stylopod muscleUBERON:000425294.43gold quality
primary visual cortexUBERON:000243694.27gold quality
neocortexUBERON:000195094.20gold quality
frontal cortexUBERON:000187094.17gold quality
ganglionic eminenceUBERON:000402394.14gold quality
amygdalaUBERON:000187694.02gold quality
pancreasUBERON:000126493.97gold quality
adrenal tissueUBERON:001830393.93gold quality
caudate nucleusUBERON:000187393.90gold quality
cerebellar vermisUBERON:000472093.82gold quality
cerebellar cortexUBERON:000212993.80gold quality
adenohypophysisUBERON:000219693.80gold quality
cerebellar hemisphereUBERON:000224593.78gold quality
mucosa of transverse colonUBERON:000499193.68gold quality
cerebellumUBERON:000203793.66gold quality
muscle of legUBERON:000138393.61gold quality

Single-cell (SCXA)

Detected in 3 experiment(s), a significant marker in 1.

ExperimentMarker?Max mean expression
E-MTAB-6058no361.04
E-HCAD-5no2.40
E-ANND-3no0.00

Regulation

Is transcription factor: no

miRNA regulators (miRDB)

9 targeting LCMT1, top 30 by miRDB confidence (max_score; target_count = how many genes the miRNA targets in total — lower means more specific):

miRNAMax scoreAvg scoremiRNA target_count
HSA-MIR-10401-5P99.9965.79948
HSA-MIR-513C-5P99.5068.421730
HSA-MIR-514B-5P99.5068.191766
HSA-MIR-444199.4966.563216
HSA-MIR-505-3P99.1969.71896
HSA-MIR-6815-3P99.1368.981530
HSA-MIR-873-5P98.8466.901348
HSA-MIR-3928-3P97.6166.531096
HSA-MIR-465495.8665.72751

Functional genomics

DepMap (CRISPR cell-line fitness): dependent in 31.1% of screened cell lines.

Literature-anchored findings (GeneRIF, showing 9)

  • LCMT-1 is important for normal progression through mitosis and cell survival and is essential for embryonic development (PMID:17724024)
  • X-ray crystal structure of human LCMT1 protein in complex with the cofactor S-adenosylmethionine (AdoMet) has been solved to a resolution of 2 A. (PMID:21206058)
  • determined crystal structures of human LCMT-1 in isolation and in complex with PP2A stabilized by a cofactor mimic. The structures show that the LCMT-1 active-site pocket recognizes the carboxyl terminus of PP2A (PMID:21292165)
  • Data indicate that PP2A holoenzyme biogenesis and activity are controlled by five PP2A modulators, consisting of alpha4, PTPA, LCMT1, PME-1 and TIPRL1, which serve to prevent promiscuous phosphatase activity until the holoenzyme is completely assembled. (PMID:22443683)
  • GSK-3beta can inhibit PP2A by increasing the inhibitory L309-demethylation involving upregulation of PME-1 and inhibition of PPMT1 (PMID:22732552)
  • alterations in the membrane localization of PP2A and Tau following down-regulation of LCMT1 may lead to PP2A and Tau dysfunction in AD. (PMID:23943618)
  • LCMT1-PME-1 methylation equilibrium is critical for regulating mitotic spindle size and thereby proper cell division (PMID:25839665)
  • We demonstrate that NNMT outcompetes leucine carboxyl methyl transferase 1 (LCMT1) for methyl transfer from principal methyl donor SAM in biological systems. Inhibiting NNMT increased the availability of methyl groups for LCMT1 to methylate PP2A, resulting in the inhibition of oncogenic serine/threonine kinases (STK). (PMID:27810903)
  • Loss of LCMT1 and biased protein phosphatase 2A heterotrimerization drive prostate cancer progression and therapy resistance. (PMID:37644036)

Cross-species orthologs

5 orthologs

OrganismSymbolGene ID
danio_reriolcmt1ENSDARG00000045140
mus_musculusLcmt1ENSMUSG00000030763
rattus_norvegicusLcmt1ENSRNOG00000014565
drosophila_melanogasterCG3793FBGN0028507
caenorhabditis_elegansWBGENE00007137

Paralogs (1): LCMT2 (ENSG00000168806)

Protein

Protein identifiers

Leucine carboxyl methyltransferase 1Q9UIC8 (reviewed: Q9UIC8)

Alternative names: Protein-leucine O-methyltransferase, [Phosphatase 2A protein]-leucine-carboxy methyltransferase 1

All UniProt accessions (7): Q9UIC8, H3BUP7, H7BYF0, I3L2E3, I3L2Q8, I3L4A2, I3L537

UniProt curated annotations — full annotation on UniProt →

Function. Methylates the carboxyl group of the C-terminal leucine residue of protein phosphatase 2A catalytic subunits to form alpha-leucine ester residues.

Similarity. Belongs to the methyltransferase superfamily. LCMT family.

Isoforms (3)

UniProt IDNamesCanonical?
Q9UIC8-11yes
Q9UIC8-22
Q9UIC8-33

RefSeq proteins (2): NP_001027563, NP_057393* (*=MANE)

Domains & families (InterPro)

IDNameType
IPR007213Ppm1/Ppm2/TcmpFamily
IPR016651LCMT1Family
IPR029063SAM-dependent_MTases_sfHomologous_superfamily

Pfam: PF04072

Enzyme classification (BRENDA):

  • EC 2.1.1.233 — [phosphatase 2A protein]-leucine-carboxy methyltransferase (BRENDA: 8 organisms, 14 substrates, 2 inhibitors, 1 Km, 0 kcat entries)

Substrate kinetics (BRENDA)

1 substrates with measured Km, best-characterized 1. Km ranges are aggregated across organisms/conditions.

SubstrateKm (mM)Measurements
[PHOSPHATASE 2A PROTEIN]-LEUCINE0.00181

Catalyzed reactions (Rhea), 1 shown:

  • [phosphatase 2A protein]-C-terminal L-leucine + S-adenosyl-L-methionine = [phosphatase 2A protein]-C-terminal L-leucine methyl ester + S-adenosyl-L-homocysteine (RHEA:48544)

UniProt features (45 total): helix 16, strand 9, sequence conflict 7, binding site 6, turn 4, splice variant 2, chain 1

Structure

Experimental structures (PDB)

3 structures.

PDBMethodResolution (Å)
3IEIX-RAY DIFFRACTION1.9
3O7WX-RAY DIFFRACTION2
3P71X-RAY DIFFRACTION2.7

Predicted structure (AlphaFold)

ModelpLDDTFraction very-high
AF-Q9UIC8-F193.800.90

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 (6): 37; 73; 98; 122; 171–172; 198

Function

Pathways and Gene Ontology

Reactome pathways

5 pathways

IDPathway
R-HSA-69273Cyclin A/B1/B2 associated events during G2/M transition
R-HSA-1640170Cell Cycle
R-HSA-453274Mitotic G2-G2/M phases
R-HSA-69275G2/M Transition
R-HSA-69278Cell Cycle, Mitotic

MSigDB gene sets: 177 (showing top): GSE18804_SPLEEN_MACROPHAGE_VS_BRAIN_TUMORAL_MACROPHAGE_DN, GOBP_NEGATIVE_REGULATION_OF_PROTEIN_CONTAINING_COMPLEX_ASSEMBLY, GOBP_CHROMOSOME_ORGANIZATION, GOBP_REGULATION_OF_CELL_CYCLE_CHECKPOINT, GOBP_REGULATION_OF_NUCLEAR_DIVISION, GOBP_CELL_CYCLE_PHASE_TRANSITION, GRAESSMANN_APOPTOSIS_BY_DOXORUBICIN_UP, MODULE_493, GOBP_CHROMOSOME_SEPARATION, CREBP1_Q2, GOBP_REGULATION_OF_CELLULAR_COMPONENT_BIOGENESIS, HUMMERICH_SKIN_CANCER_PROGRESSION_DN, GOBP_NEGATIVE_REGULATION_OF_CELLULAR_COMPONENT_ORGANIZATION, SHEDDEN_LUNG_CANCER_GOOD_SURVIVAL_A5, KEGG_HISTIDINE_METABOLISM

GO Biological Process (10): G2/M transition of mitotic cell cycle (GO:0000086), protein methylation (GO:0006479), C-terminal protein methylation (GO:0006481), regulation of glucose metabolic process (GO:0010906), negative regulation of protein-containing complex assembly (GO:0031333), protein modification process (GO:0036211), regulation of apoptotic process (GO:0042981), regulation of mitotic cell cycle spindle assembly checkpoint (GO:0090266), regulation of signal transduction (GO:0009966), methylation (GO:0032259)

GO Molecular Function (7): protein C-terminal carboxyl O-methyltransferase activity (GO:0003880), S-adenosylmethionine-dependent methyltransferase activity (GO:0008757), protein C-terminal leucine carboxyl O-methyltransferase activity (GO:0018423), protein binding (GO:0005515), methyltransferase activity (GO:0008168), protein methyltransferase activity (GO:0008276), transferase activity (GO:0016740)

GO Cellular Component (2): nucleoplasm (GO:0005654), cytosol (GO:0005829)

Reactome top-level categories

Rollup of top-4 pathways:

CategoryPathways
G2/M Transition1
Cell Cycle, Mitotic1
Mitotic G2-G2/M phases1
Cell Cycle1

GO top-level categories

Rollup of top GO terms by namespace:

CategoryTerms
methyltransferase activity2
cellular anatomical structure2
mitotic cell cycle1
mitotic cell cycle phase transition1
cell cycle G2/M phase transition1
protein alkylation1
macromolecule methylation1
protein methylation1
C-terminal protein amino acid modification1
glucose metabolic process1
regulation of carbohydrate metabolic process1
regulation of small molecule metabolic process1
regulation of protein-containing complex assembly1
negative regulation of cellular component organization1
protein-containing complex assembly1
protein metabolic process1
macromolecule modification1
apoptotic process1
regulation of programmed cell death1
regulation of mitotic nuclear division1
mitotic spindle assembly checkpoint signaling1
regulation of mitotic sister chromatid separation1
regulation of mitotic metaphase/anaphase transition1
regulation of mitotic sister chromatid segregation1
regulation of mitotic spindle checkpoint1
signal transduction1
regulation of cell communication1
regulation of signaling1
regulation of response to stimulus1
metabolic process1
protein carboxyl O-methyltransferase activity1
protein C-terminal carboxyl O-methyltransferase activity1
S-adenosylmethionine-dependent methyltransferase activity1
binding1
transferase activity, transferring one-carbon groups1
catalytic activity, acting on a protein1
catalytic activity1
nuclear lumen1
cytoplasm1

Protein interactions and networks

STRING

1028 interactions, top by confidence (×1000):

Protein AProtein BPartner UniProtScore
LCMT1PPP2R2AP50409965
LCMT1PPP2CAP05323931
LCMT1PPME1Q9Y570915
LCMT1PTPAQ15257744
LCMT1TIPRLO75663710
LCMT1PPP2R1AP30153608
LCMT1PPP4CP33172589
LCMT1PPP2R3BQ9Y5P8586
LCMT1PPP2R3AQ06190585
LCMT1NPRL3Q12980569
LCMT1PPP2R5AQ15172565
LCMT1AQP8O94778550
LCMT1PPP2R5DQ14738539
LCMT1NPRL2Q8WTW4531
LCMT1MINK1Q8N4C8527

IntAct

12 interactions, top by confidence:

ABTypeScore
FXR2LCMT1psi-mi:“MI:0915”(physical association)0.510
LCMT1FXR2psi-mi:“MI:0915”(physical association)0.510
PPP2CALCMT1psi-mi:“MI:0915”(physical association)0.400
LCMT1VPS37Cpsi-mi:“MI:0915”(physical association)0.400
CFTRLCMT1psi-mi:“MI:0915”(physical association)0.370
LCMT1TAB1psi-mi:“MI:0915”(physical association)0.370
LCMT1PPP4Cpsi-mi:“MI:0914”(association)0.350
DND1HNRNPCL1psi-mi:“MI:0914”(association)0.350
TGDSGPD1psi-mi:“MI:0914”(association)0.350
LCMT1solApsi-mi:“MI:0915”(physical association)0.000

BioGRID (35): PPP2CA (Affinity Capture-MS), PPP4C (Affinity Capture-MS), EIF1AX (Affinity Capture-MS), PPP4R2 (Affinity Capture-MS), LCMT1 (Two-hybrid), LCMT1 (Affinity Capture-Western), LCMT1 (Co-fractionation), NECAP1 (Co-fractionation), TANGO2 (Co-fractionation), PPP2CA (Affinity Capture-MS), PPP4R2 (Affinity Capture-MS), PPP4C (Affinity Capture-MS), LCMT1 (Affinity Capture-MS), LCMT1 (Negative Genetic), LCMT1 (Negative Genetic)

ESM2 similar proteins: A2AV36, A2VD33, A4QN59, A4QP75, A6QQV6, B0WSX1, B3MZN7, B4PYH5, B8A5G9, D3ZG52, D9IVE5, E1BMP7, F1QCV2, O95470, P51530, Q14CH1, Q16GH0, Q16P90, Q28CZ7, Q2VPA6, Q32PX9, Q3T0H0, Q3TZM9, Q4KLT3, Q4V7D6, Q502I6, Q58E95, Q5U4E8, Q5U534, Q5ZIB9, Q5ZKG3, Q655R6, Q6NTR1, Q6P4Z6, Q6PCI6, Q6ZQJ5, Q8AWD2, Q8BIP0, Q8GWT4, Q8LGM7

Diamond homologs: O60294, O94257, P0CO56, P0CO57, P46554, Q3T0H0, Q4ICG8, Q4WS57, Q5AQJ2, Q5XIA3, Q5Z8K3, Q60YU0, Q6C997, Q6P4Z6, Q75AW4, Q8BYR1, Q8VY08, Q9UIC8, Q6BQD2, Q7SAP7, Q4P4G2, Q9P3K9, Q5A387, Q6FUI5, Q04081, Q6CWW0, Q759U5, O60157, Q08282, Q5A931, Q6FXA5, A1KGK7, A5U0B2, P9WFI6, P9WFI7, Q7U1E6, Q9LR78, Q2U6D4, Q4WVD1, Q5BH52

SIGNOR signaling

2 interactions.

AEffectBMechanism
LCMT1“up-regulates activity”PPP2CAmethylation
LCMT1“up-regulates activity”PPP2CBmethylation

Disease & clinical

Clinical variants and AI predictions

ClinVar

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

ClassificationCount (floor)
Pathogenic0
Likely pathogenic0
Uncertain significance48
Likely benign2
Benign1

Top pathogenic / likely-pathogenic (0)

SpliceAI

2117 predictions. Top by Δscore:

VariantEffectΔscore
16:25161170:G:GTdonor_gain1.0000
16:25161179:C:Gdonor_gain1.0000
16:25161184:GAAAT:Gdonor_gain1.0000
16:25161205:G:GGdonor_gain1.0000
16:25164596:A:Gacceptor_gain1.0000
16:25164726:G:GTdonor_gain1.0000
16:25169106:TCCTA:Tacceptor_loss1.0000
16:25169107:CCTAG:Cacceptor_loss1.0000
16:25169108:CTAGG:Cacceptor_loss1.0000
16:25169109:TAGGT:Tacceptor_loss1.0000
16:25169110:A:AGacceptor_gain1.0000
16:25169110:AGG:Aacceptor_loss1.0000
16:25169111:G:GGacceptor_gain1.0000
16:25169195:C:Tdonor_gain1.0000
16:25169209:CACAG:Cdonor_loss1.0000
16:25169211:CAGG:Cdonor_loss1.0000
16:25169212:AG:Adonor_loss1.0000
16:25169213:GGTC:Gdonor_loss1.0000
16:25169214:G:Adonor_loss1.0000
16:25169215:T:Adonor_loss1.0000
16:25170706:C:Gacceptor_gain1.0000
16:25174936:GGATA:Gacceptor_gain1.0000
16:25175020:G:GTdonor_gain1.0000
16:25175023:GAAA:Gdonor_gain1.0000
16:25175024:A:Tdonor_gain1.0000
16:25175030:GCTTG:Gdonor_gain1.0000
16:25175031:C:Gdonor_gain1.0000
16:25175033:TGG:Tdonor_loss1.0000
16:25175035:G:GGdonor_gain1.0000
16:25175036:T:Adonor_loss1.0000

AlphaMissense

2198 scored. Top likely-pathogenic:

VariantProtein changeam_pathogenicity
16:25169130:T:CF237L0.999
16:25169132:T:AF237L0.999
16:25169132:T:GF237L0.999
16:25174963:A:TE304V0.999
16:25111994:G:CK37N0.998
16:25111994:G:TK37N0.998
16:25132512:T:AW106R0.998
16:25132512:T:CW106R0.998
16:25169155:T:CL245P0.998
16:25128480:C:AA40E0.997
16:25128565:A:CR68S0.997
16:25128565:A:TR68S0.997
16:25140207:G:CD122H0.997
16:25164621:A:TE198V0.997
16:25164625:T:GC199W0.997
16:25169131:T:GF237C0.997
16:25170738:T:AW273R0.997
16:25170738:T:CW273R0.997
16:25128558:T:CI66T0.996
16:25132402:G:AG69E0.996
16:25132411:C:AA72D0.996
16:25132500:G:CD102H0.996
16:25140208:A:TD122V0.996
16:25140233:G:CK130N0.996
16:25140233:G:TK130N0.996
16:25161153:G:CR173P0.996
16:25164635:T:CY203H0.996
16:25169143:T:CM241T0.996
16:25169144:G:AM241I0.996
16:25169144:G:CM241I0.996

dbSNP variants (sampled 300 via entrez): RS1000013234 (16:25151616 G>A), RS1000061360 (16:25151841 C>T), RS1000113500 (16:25152147 G>T), RS1000115938 (16:25137827 T>G), RS1000144007 (16:25135527 G>A,T), RS1000229257 (16:25168113 A>G,T), RS1000239972 (16:25129415 G>A), RS1000242131 (16:25130166 C>T), RS1000269995 (16:25168382 A>G), RS1000294471 (16:25130302 T>C), RS1000361347 (16:25157533 G>A), RS1000471202 (16:25112990 T>C), RS1000523348 (16:25146341 A>C,G,T), RS1000554747 (16:25147987 G>A), RS1000570823 (16:25173974 C>T)

Disease associations

OMIM: gene MIM:610286 | 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):

StudyTraitp-value
GCST002935_23Lead levels8.000000e-06

Drugs & pharmacology

Drug and pharmacology data

Is drug target: no

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

CTD chemical–gene interactions

28 total (human), top 28 by PubMed support.

ChemicalActions (top 5)PubMed papers
sodium arseniteaffects methylation, decreases expression, increases abundance, increases expression4
Arsenicdecreases expression, increases abundance, increases expression2
Valproic Acidaffects expression, increases expression2
Cyclosporineincreases expression2
aristolochic acid Iincreases expression1
GSK-J4increases expression1
alpha-pineneaffects cotreatment, increases oxidation, increases abundance1
bisphenol Aaffects cotreatment, decreases methylation1
trichostatin Aaffects expression1
methacrylaldehydeaffects cotreatment, increases oxidation, increases abundance1
di-n-butylphosphoric acidaffects expression1
bisphenol Sincreases methylation1
Temozolomidedecreases expression1
Sunitinibincreases expression1
Fulvestrantaffects cotreatment, decreases methylation1
Acetaminophenincreases expression1
Acroleinincreases abundance, affects cotreatment, increases oxidation1
Air Pollutantsaffects cotreatment, increases abundance, increases oxidation1
Arecolinedecreases expression1
Benzo(a)pyreneincreases methylation1
Carbamazepineaffects expression1
Ozoneaffects cotreatment, increases oxidation, increases abundance1
Nocodazoledecreases response to substance1
Aflatoxin B1decreases methylation1
Sodium Seleniteincreases expression1
Okadaic Acidincreases expression1
Lactic Aciddecreases expression1
Volatile Organic Compoundsaffects cotreatment, increases oxidation1

Cellosaurus cell lines

3 cell lines: 3 cancer cell line

First 10 cell lines (id-ordered, not curated):

CellosaurusNameCategorySex
CVCL_SV37HAP1 LCMT1 (-) 1Cancer cell lineMale
CVCL_SV38HAP1 LCMT1 (-) 2Cancer cell lineMale
CVCL_SV39HAP1 LCMT1 (-) 3Cancer cell lineMale

Clinical trials (associated diseases)

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

No linked Atlas pages yet — the cross-entity mesh grows as the corpus expands.