Standard name Systematic name Name description Description
ARE2 YNR019W Acyl-CoA:sterol acyltransferase Acyl-CoA:sterol acyltransferase; endoplasmic reticulum enzyme that contributes the major sterol esterification activity in the presence of oxygen; ARE2 has a paralog, ARE1, that arose from the whole genome duplication
Visualize the interactome of ARE2
Links to external databases:
  SGD   |   KEGG   |  

Cell cycle phase and timing of transcription peak

Cell cycle phase Time (min)

CYCLoPs localization & abundance

WT1 WT2 WT3
Cytoplasm 0.697 0.888 0.700
ER 0.267 0.052 0.172
Mito NaN 0.097 0.081
Vac/Vac Memb NaN NaN 0.068

GFP localization & abundance

GFP localization GFP abundance
ER 279

GO term count

Metabolism Cell cycle Cell division Signal transduction DNA replication
ARE2 2 0 0 0 0

Enzyme information

Catalyzed reactions in Yeast8
r_2387 (diacylglycerol acyltransferase (1-16:1, 2-18:1, 3-18:0), ER membrane), r_0132 (acyl-CoA:sterol acyltransferase (palmitoleoyl-CoA:ergosterol), ER membrane), r_2374 (diacylglycerol acyltransferase (1-18:1, 2-16:1, 3-16:0), ER membrane), r_2394 (diacylglycerol acyltransferase (1-16:1, 2-16:1, 3-18:1), ER membrane), r_2381 (diacylglycerol acyltransferase (1-18:0, 2-18:1, 3-16:1), ER membrane), r_2368 (diacylglycerol acyltransferase (1-16:0, 2-16:1, 3-16:0), ER membrane), r_2388 (diacylglycerol acyltransferase (1-18:0, 2-16:1, 3-18:0), ER membrane), r_2375 (diacylglycerol acyltransferase (1-18:1, 2-18:1, 3-16:0), ER membrane), r_2369 (diacylglycerol acyltransferase (1-16:0, 2-18:1, 3-16:0), ER membrane), r_2395 (diacylglycerol acyltransferase (1-16:1, 2-18:1, 3-18:1), ER membrane), r_2382 (diacylglycerol acyltransferase (1-18:1, 2-16:1, 3-16:1), ER membrane), r_2389 (diacylglycerol acyltransferase (1-18:0, 2-18:1, 3-18:0), ER membrane), r_2376 (diacylglycerol acyltransferase (1-16:0, 2-16:1, 3-16:1), ER membrane), r_2396 (diacylglycerol acyltransferase (1-18:0, 2-16:1, 3-18:1), ER membrane), r_2383 (diacylglycerol acyltransferase (1-18:1, 2-18:1, 3-16:1), ER membrane), r_2390 (diacylglycerol acyltransferase (1-18:1, 2-16:1, 3-18:0), ER membrane), r_2370 (diacylglycerol acyltransferase (1-16:1, 2-16:1, 3-16:0), ER membrane), r_2377 (diacylglycerol acyltransferase (1-16:0, 2-18:1, 3-16:1), ER membrane), r_2397 (diacylglycerol acyltransferase (1-18:0, 2-18:1, 3-18:1), ER membrane), r_2384 (diacylglycerol acyltransferase (1-16:0, 2-16:1, 3-18:0), ER membrane), r_2371 (diacylglycerol acyltransferase (1-16:1, 2-18:1, 3-16:0), ER membrane), r_2391 (diacylglycerol acyltransferase (1-18:1, 2-18:1, 3-18:0), ER membrane), r_2378 (diacylglycerol acyltransferase (1-16:1, 2-16:1, 3-16:1), ER membrane), r_2398 (diacylglycerol acyltransferase (1-18:1, 2-16:1, 3-18:1), ER membrane), r_2385 (diacylglycerol acyltransferase (1-16:0, 2-18:1, 3-18:0), ER membrane), r_2372 (diacylglycerol acyltransferase (1-18:0, 2-16:1, 3-16:0), ER membrane), r_2392 (diacylglycerol acyltransferase (1-16:0, 2-16:1, 3-18:1), ER membrane), r_0127 (acyl-CoA:sterol acyltransferase (oleoyl-CoA:ergosterol), ER membrane), r_2379 (diacylglycerol acyltransferase (1-16:1, 2-18:1, 3-16:1), ER membrane), r_2399 (diacylglycerol acyltransferase (1-18:1, 2-18:1, 3-18:1), ER membrane), r_2386 (diacylglycerol acyltransferase (1-16:1, 2-16:1, 3-18:0), ER membrane), r_2373 (diacylglycerol acyltransferase (1-18:0, 2-18:1, 3-16:0), ER membrane), r_2393 (diacylglycerol acyltransferase (1-16:0, 2-18:1, 3-18:1), ER membrane), r_2380 (diacylglycerol acyltransferase (1-18:0, 2-16:1, 3-16:1), ER membrane)

List of interactors

Use the search utility to find the interactor you are looking for. By clicking the column headers the table will be sorted on that column. Use shift+click to sort on multiple columns. Default sorting is on number of experiments, number of unique methods and the number of publications, and alphabetical on standard name, in that order.
Standard name Systematic name Name description Type #Experiments #Methods #Publications Evidence
LRO1 YNR008W Acyltransferase that converts diacylglycerol to triacylglycerol (TGA) genetic 12 4 9 Phenotypic Enhancement, Phenotypic Enhancement, Synthetic Growth Defect, Phenotypic Enhancement, Synthetic Lethality, Phenotypic Enhancement, Phenotypic Enhancement, Phenotypic Enhancement, Phenotypic Suppression, Synthetic Growth Defect, Phenotypic Suppression, Phenotypic Enhancement
DGA1 YOR245C Diacylglycerol acyltransferase genetic 12 4 9 Phenotypic Enhancement, Phenotypic Enhancement, Synthetic Growth Defect, Phenotypic Enhancement, Synthetic Lethality, Phenotypic Enhancement, Phenotypic Enhancement, Phenotypic Enhancement, Phenotypic Suppression, Synthetic Growth Defect, Phenotypic Suppression, Phenotypic Enhancement
ARE1 YCR048W Acyl-CoA:sterol acyltransferase genetic 11 4 9 Phenotypic Enhancement, Phenotypic Enhancement, Phenotypic Enhancement, Phenotypic Enhancement, Synthetic Growth Defect, Phenotypic Enhancement, Synthetic Lethality, Negative Genetic, Phenotypic Enhancement, Phenotypic Enhancement, Synthetic Lethality
SCS7 YMR272C Sphingolipid alpha-hydroxylase genetic 5 1 3 Positive Genetic, Positive Genetic, Positive Genetic, Positive Genetic, Positive Genetic
ERG3 YLR056W C-5 sterol desaturase genetic 4 1 4 Negative Genetic, Negative Genetic, Negative Genetic, Negative Genetic
UBX2 YML013W Bridging factor involved in ER-associated protein degradation (ERAD) genetic 3 2 2 Negative Genetic, Negative Genetic, Phenotypic Enhancement
RDH54 YBR073W DNA-dependent ATPase genetic 3 1 2 Negative Genetic, Negative Genetic, Negative Genetic
DCC1 YCL016C Subunit of a complex with Ctf8p and Ctf18p genetic 3 1 2 Negative Genetic, Negative Genetic, Negative Genetic
RAD51 YER095W Strand exchange protein genetic 3 1 2 Negative Genetic, Negative Genetic, Negative Genetic
SDH9 YJL045W Minor succinate dehydrogenase isozyme genetic 3 1 2 Negative Genetic, Negative Genetic, Negative Genetic
RPS30A YLR287C-A Protein component of the small (40S) ribosomal subunit genetic 3 1 2 Negative Genetic, Negative Genetic, Negative Genetic
PAC1 YOR269W Regulator of dynein, involved in intracellular transport genetic 3 1 2 Negative Genetic, Negative Genetic, Negative Genetic
PDE2 YOR360C High-affinity cyclic AMP phosphodiesterase genetic 3 1 2 Negative Genetic, Negative Genetic, Negative Genetic
VPS1 YKR001C Dynamin-like GTPase required for vacuolar sorting genetic 3 1 2 Negative Genetic, Negative Genetic, Negative Genetic
FKH1 YIL131C Forkhead family transcription factor regulation 2 1 2 chromatin immunoprecipitation-chip evidence, chromatin immunoprecipitation-chip evidence
RBK1 YCR036W Ribokinase, phosphorylates ribose to ribose-5-phosphate genetic 2 1 2 Negative Genetic, Negative Genetic
BUD31 YCR063W Component of the SF3b subcomplex of the U2 snRNP genetic 2 1 2 Negative Genetic, Negative Genetic
PMT5 YDL093W Protein O-mannosyltransferase genetic 2 1 2 Negative Genetic, Negative Genetic
KAP122 YGL016W Karyopherin beta genetic 2 1 2 Negative Genetic, Negative Genetic
MOT3 YMR070W Transcriptional repressor, activator genetic 2 1 2 Negative Genetic, Negative Genetic
PAH1 YMR165C Mg2+-dependent phosphatidate (PA) phosphatase genetic 2 1 2 Phenotypic Enhancement, Phenotypic Enhancement
CHO2 YGR157W Phosphatidylethanolamine methyltransferase (PEMT) genetic 2 1 2 Negative Genetic, Negative Genetic
PDR11 YIL013C ATP-binding cassette (ABC) transporter physical 2 2 1 PCA, Affinity Capture-Western
SSM4 YIL030C Membrane-embedded ubiquitin-protein ligase and retrotranslocase genetic 2 2 1 Phenotypic Enhancement, Synthetic Lethality
YNL046W YNL046W Putative protein of unknown function genetic 2 1 1 Negative Genetic, Negative Genetic
BFR1 YOR198C Component of mRNP complexes associated with polyribosomes genetic 2 1 1 Positive Genetic, Positive Genetic
GET2 YER083C Subunit of the GET complex genetic 2 1 1 Positive Genetic, Positive Genetic
YMD8 YML038C Putative nucleotide sugar transporter genetic 2 1 1 Positive Genetic, Positive Genetic
YAR029W YAR029W Member of DUP240 gene family but contains no transmembrane domains genetic 2 1 1 Negative Genetic, Negative Genetic
HSP78 YDR258C Oligomeric mitochondrial matrix chaperone genetic 2 1 1 Negative Genetic, Negative Genetic
ICE2 YIL090W Integral ER membrane protein with type-III transmembrane domains genetic 2 1 1 Negative Genetic, Negative Genetic
MET12 YPL023C Protein with MTHFR activity in vitro genetic 2 1 1 Negative Genetic, Negative Genetic
YPT6 YLR262C Rab family GTPase genetic 2 1 1 Negative Genetic, Negative Genetic
HOF1 YMR032W F-BAR protein that regulates actin cytoskeleton organization genetic 2 1 1 Positive Genetic, Positive Genetic
POR1 YNL055C Mitochondrial porin (voltage-dependent anion channel) genetic 2 1 1 Negative Genetic, Negative Genetic
YME1 YPR024W Catalytic subunit of i-AAA protease complex genetic 2 1 1 Positive Genetic, Positive Genetic
GCN5 YGR252W Catalytic subunit of ADA and SAGA histone acetyltransferase complexes regulation 1 1 1 chromatin immunoprecipitation-chip evidence
RFX1 YLR176C Major transcriptional repressor of DNA-damage-regulated genes regulation 1 1 1 chromatin immunoprecipitation-chip evidence
FKH2 YNL068C Forkhead family transcription factor regulation 1 1 1 chromatin immunoprecipitation-chip evidence
SUA7 YPR086W Transcription factor TFIIB regulation 1 1 1 chromatin immunoprecipitation-chip evidence
UME6 YDR207C Rpd3L histone deacetylase complex subunit regulation 1 1 1 DNA to cDNA expression microarray evidence
PAF1 YBR279W Component of the Paf1p complex involved in transcription elongation regulation 1 1 1 chromatin immunoprecipitation-chip evidence
AMN1 YBR158W Modulator of cell separation and mitotic exit genetic 1 1 1 Negative Genetic
ACC1 YNR016C Acetyl-CoA carboxylase, biotin containing enzyme genetic 1 1 1 Phenotypic Enhancement
PTC1 YDL006W Type 2C protein phosphatase (PP2C) physical 1 1 1 Affinity Capture-MS
HSP82 YPL240C Hsp90 chaperone physical 1 1 1 Two-hybrid
ATG1 YGL180W Protein serine/threonine kinase physical 1 1 1 Biochemical Activity
FUS3 YBL016W Mitogen-activated serine/threonine protein kinase involved in mating physical 1 1 1 Biochemical Activity
PTK2 YJR059W Serine/threonine protein kinase physical 1 1 1 Biochemical Activity
STE20 YHL007C Cdc42p-activated signal transducing kinase physical 1 1 1 Biochemical Activity
TPK1 YJL164C cAMP-dependent protein kinase catalytic subunit physical 1 1 1 Biochemical Activity
YCK1 YHR135C Palmitoylated plasma membrane-bound casein kinase I (CK1) isoform physical 1 1 1 Biochemical Activity
YCK2 YNL154C Palmitoylated plasma membrane-bound casein kinase I (CK1) isoform physical 1 1 1 Biochemical Activity
HRK1 YOR267C Protein kinase physical 1 1 1 Biochemical Activity
NAB2 YGL122C Nuclear polyadenylated RNA-binding protein physical 1 1 1 Affinity Capture-RNA
SND3 YBR106W Involved in SRP-independent protein targeting to the ER physical 1 1 1 PCA
IFA38 YBR159W Microsomal beta-keto-reductase physical 1 1 1 PCA
STE24 YJR117W Highly conserved zinc metalloprotease physical 1 1 1 PCA
PHO85 YPL031C Cyclin-dependent kinase physical 1 1 1 Biochemical Activity
ARE2 YNR019W Acyl-CoA:sterol acyltransferase physical 1 1 1 Affinity Capture-Western
COS8 YHL048W Endosomal protein involved in turnover of plasma membrane proteins physical 1 1 1 PCA
COS12 YGL263W Endosomal protein involved in turnover of plasma membrane proteins physical 1 1 1 PCA
GLT1 YDL171C NAD(+)-dependent glutamate synthase (GOGAT) physical 1 1 1 PCA
MFB1 YDR219C Mitochondria-associated F-box protein physical 1 1 1 PCA
NUP84 YDL116W Subunit of the Nup84p subcomplex of the nuclear pore complex (NPC) physical 1 1 1 PCA
SIP18 YMR175W Phospholipid-binding hydrophilin physical 1 1 1 PCA
YJR096W YJR096W Xylose and arabinose reductase physical 1 1 1 PCA
SLU7 YDR088C RNA splicing factor physical 1 1 1 PCA
MTF1 YMR228W Mitochondrial RNA polymerase specificity factor physical 1 1 1 PCA
ATP8 Q0080 Subunit 8 of the F0 sector of mitochondrial F1F0 ATP synthase physical 1 1 1 PCA
AUS1 YOR011W Plasma membrane sterol transporter of the ATP-binding cassette family physical 1 1 1 Affinity Capture-Western
HOG1 YLR113W Mitogen-activated protein kinase involved in osmoregulation physical 1 1 1 Co-localization
DHH1 YDL160C Cytoplasmic DEAD-box helicase and mRNA decapping activator physical 1 1 1 Affinity Capture-RNA
PUB1 YNL016W Poly (A)+ RNA-binding protein physical 1 1 1 Affinity Capture-MS
SPT16 YGL207W Subunit of the heterodimeric FACT complex (Spt16p-Pob3p) physical 1 1 1 Affinity Capture-MS
ARV1 YLR242C Cortical ER protein genetic 1 1 1 Synthetic Lethality
BRR6 YGL247W Essential nuclear envelope integral membrane protein genetic 1 1 1 Synthetic Lethality
SHR3 YDL212W Endoplasmic reticulum packaging chaperone genetic 1 1 1 Negative Genetic
GIM4 YEL003W Subunit of the heterohexameric cochaperone prefoldin complex genetic 1 1 1 Negative Genetic
HEM2 YGL040C Aminolevulinate dehydratase genetic 1 1 1 Negative Genetic
FRT2 YAL028W Tail-anchored ER membrane protein of unknown function genetic 1 1 1 Negative Genetic
PEX32 YBR168W Peroxisomal integral membrane protein genetic 1 1 1 Negative Genetic
BAR1 YIL015W Aspartyl protease secreted to periplasmic space of mating type a cell genetic 1 1 1 Negative Genetic
MCA1 YOR197W Ca2+-dependent cysteine protease genetic 1 1 1 Negative Genetic
ARK1 YNL020C Ser/Thr protein kinase genetic 1 1 1 Negative Genetic
RIC1 YLR039C Protein involved in retrograde transport to the cis-Golgi network genetic 1 1 1 Negative Genetic
ATP14 YLR295C Subunit h of the F0 sector of mitochondrial F1F0 ATP synthase genetic 1 1 1 Positive Genetic
GAP1 YKR039W General amino acid permease genetic 1 1 1 Negative Genetic
PMA1 YGL008C Plasma membrane P2-type H+-ATPase genetic 1 1 1 Negative Genetic
PPT2 YPL148C Phosphopantetheine:protein transferase (PPTase) genetic 1 1 1 Negative Genetic
GPH1 YPR160W Glycogen phosphorylase required for the mobilization of glycogen genetic 1 1 1 Negative Genetic
CSG2 YBR036C Endoplasmic reticulum membrane protein genetic 1 1 1 Positive Genetic
RGP1 YDR137W Subunit of a Golgi membrane exchange factor (Ric1p-Rgp1p) genetic 1 1 1 Negative Genetic
DOP1 YDR141C Protein involved in vesicular transport at trans-Golgi network (TGN) genetic 1 1 1 Positive Genetic
IPK1 YDR315C Inositol 1,3,4,5,6-pentakisphosphate 2-kinase genetic 1 1 1 Negative Genetic
GLN3 YER040W Transcriptional activator in nitrogen catabolite repression system genetic 1 1 1 Negative Genetic
LAS1 YKR063C Endonuclease involved in pre-rRNA processing at both ends of ITS2 genetic 1 1 1 Negative Genetic
ERG2 YMR202W C-8 sterol isomerase genetic 1 1 1 Negative Genetic
ERG12 YMR208W Mevalonate kinase genetic 1 1 1 Negative Genetic
LAP3 YNL239W Cysteine aminopeptidase with homocysteine-thiolactonase activity genetic 1 1 1 Negative Genetic
UBC7 YMR022W Ubiquitin conjugating enzyme genetic 1 1 1 Synthetic Lethality
GPI11 YDR302W ER membrane protein involved in a late step of GPI anchor assembly genetic 1 1 1 Positive Genetic
GPI19 YDR437W Subunit of GPI-GlcNAc transferase involved in synthesis of GlcNAc-PI genetic 1 1 1 Positive Genetic
GPI13 YLL031C ER membrane localized phosphoryltransferase genetic 1 1 1 Positive Genetic
PDX3 YBR035C Pyridoxine (pyridoxamine) phosphate oxidase genetic 1 1 1 Positive Genetic
YGL114W YGL114W Putative protein of unknown function genetic 1 1 1 Positive Genetic
RER2 YBR002C Forms the dehydrodolichyl diphosphate synthase (DDS) complex with NUS1 genetic 1 1 1 Negative Genetic
CDC48 YDL126C AAA ATPase with protein-unfoldase activity genetic 1 1 1 Negative Genetic
CCT6 YDR188W Subunit of the cytosolic chaperonin Cct ring complex genetic 1 1 1 Negative Genetic
WBP1 YEL002C Beta subunit of the oligosaccharyl transferase glycoprotein complex genetic 1 1 1 Negative Genetic
DUO1 YGL061C Essential subunit of the Dam1 complex (aka DASH complex) genetic 1 1 1 Negative Genetic
RPB11 YOL005C RNA polymerase II subunit B12.5 genetic 1 1 1 Negative Genetic
SMX3 YPR182W Core Sm protein Sm F genetic 1 1 1 Negative Genetic
SCS22 YBL091C-A Protein involved in regulation of phospholipid metabolism genetic 1 1 1 Negative Genetic
SEA4 YBL104C Subunit of SEACAT, a subcomplex of the SEA complex genetic 1 1 1 Negative Genetic
ARL1 YBR164C Soluble GTPase with a role in regulation of membrane traffic genetic 1 1 1 Negative Genetic
BSD2 YBR290W Heavy metal ion homeostasis protein genetic 1 1 1 Negative Genetic
YCL001W-B YCL001W-B Putative protein of unknown function genetic 1 1 1 Negative Genetic
SED4 YCR067C Integral ER membrane protein that stimulates Sar1p GTPase activity genetic 1 1 1 Negative Genetic
UBP1 YDL122W Ubiquitin-specific protease genetic 1 1 1 Negative Genetic
YDL180W YDL180W Putative protein of unknown function genetic 1 1 1 Negative Genetic
MGT1 YDL200C DNA repair methyltransferase (6-O-methylguanine-DNA methylase) genetic 1 1 1 Negative Genetic
MRX14 YDR115W Putative mitochondrial ribosomal protein of the large subunit genetic 1 1 1 Negative Genetic
TMA64 YDR117C Protein of unknown function that associates with ribosomes genetic 1 1 1 Negative Genetic
DPL1 YDR294C Dihydrosphingosine phosphate lyase genetic 1 1 1 Negative Genetic
SHO1 YER118C Transmembrane osmosensor for filamentous growth and HOG pathways genetic 1 1 1 Negative Genetic
DOC1 YGL240W Processivity factor genetic 1 1 1 Negative Genetic
BRL1 YHR036W Essential nuclear envelope/ER integral membrane protein genetic 1 1 1 Synthetic Lethality
YHR050W-A YHR050W-A Protein of unknown function genetic 1 1 1 Negative Genetic
MNT3 YIL014W Alpha-1,3-mannosyltransferase genetic 1 1 1 Negative Genetic
EGH1 YIR007W Steryl-beta-glucosidase with broad specificity for aglycones genetic 1 1 1 Negative Genetic
YJL047C-A YJL047C-A Putative protein of unknown function genetic 1 1 1 Negative Genetic
BNA3 YJL060W Kynurenine aminotransferase genetic 1 1 1 Negative Genetic
MLO127 YJR039W Mitochondrial protein of unknown function genetic 1 1 1 Negative Genetic
YJR149W YJR149W Putative protein of unknown function genetic 1 1 1 Negative Genetic
SEG2 YKL105C Eisosome component genetic 1 1 1 Negative Genetic
PCT1 YGR202C Cholinephosphate cytidylyltransferase genetic 1 1 1 Phenotypic Suppression
DGK1 YOR311C Diacylglycerol kinase genetic 1 1 1 Phenotypic Suppression
ERG24 YNL280C C-14 sterol reductase genetic 1 1 1 Negative Genetic
RPS11B YBR048W Protein component of the small (40S) ribosomal subunit genetic 1 1 1 Negative Genetic
VMS1 YDR049W Peptidyl-tRNA hydrolase that releases stalled peptides from ribosomes, genetic 1 1 1 Negative Genetic
IPT1 YDR072C Inositolphosphotransferase genetic 1 1 1 Negative Genetic
SPS2 YDR522C Protein expressed during sporulation genetic 1 1 1 Negative Genetic
SPO11 YHL022C Meiosis-specific protein required for meiotic recombination genetic 1 1 1 Negative Genetic
RPL14A YKL006W Ribosomal 60S subunit protein L14A genetic 1 1 1 Negative Genetic
VPS51 YKR020W Component of the GARP (Golgi-associated retrograde protein) complex genetic 1 1 1 Negative Genetic
RIM11 YMR139W Protein kinase genetic 1 1 1 Negative Genetic
MED1 YPR070W Subunit of the RNA polymerase II mediator complex genetic 1 1 1 Negative Genetic
WHI5 YOR083W Repressor of G1 transcription genetic 1 1 1 Negative Genetic
BIR1 YJR089W Subunit of chromosomal passenger complex (CPC) genetic 1 1 1 Negative Genetic
TUB4 YLR212C Gamma-tubulin genetic 1 1 1 Synthetic Rescue
HRQ1 YDR291W 3'-5' DNA helicase of the conserved RecQ family genetic 1 1 1 Negative Genetic
SGS1 YMR190C RecQ family nucleolar DNA helicase genetic 1 1 1 Negative Genetic
UPC2 YDR213W Sterol regulatory element binding protein genetic 1 1 1 Phenotypic Enhancement
DPP1 YDR284C Diacylglycerol pyrophosphate (DGPP) phosphatase genetic 1 1 1 Phenotypic Enhancement
LPP1 YDR503C Lipid phosphate phosphatase genetic 1 1 1 Phenotypic Enhancement
ALG5 YPL227C UDP-glucose:dolichyl-phosphate glucosyltransferase physical 1 1 1 PCA
APQ12 YIL040W Nuclear envelope/ER integral membrane protein genetic 1 1 1 Synthetic Growth Defect