ID   SSY2_ARATH              Reviewed;         792 AA.
AC   Q9MAC8;
DT   31-OCT-2012, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2000, sequence version 1.
DT   04-NOV-2026, entry version 147.
DE   RecName: Full=Starch synthase 2, chloroplastic/amyloplastic;
DE            Short=AtSS2;
DE            EC=2.4.1.21;
DE   AltName: Full=Soluble starch synthase II;
DE   Flags: Precursor;
GN   Name=SS2; OrderedLocusNames=At3g01180; ORFNames=T4P13.13;
OS   Arabidopsis thaliana (Mouse-ear cress).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   rosids; malvids; Brassicales; Brassicaceae; Camelineae; Arabidopsis.
OX   NCBI_TaxID=3702;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=cv. Columbia;
RX   PubMed=11130713; DOI=10.1038/35048706;
RA   Salanoubat M., Lemcke K., Rieger M., Ansorge W., Unseld M., Fartmann B.,
RA   Valle G., Bloecker H., Perez-Alonso M., Obermaier B., Delseny M.,
RA   Boutry M., Grivell L.A., Mache R., Puigdomenech P., De Simone V.,
RA   Choisne N., Artiguenave F., Robert C., Brottier P., Wincker P.,
RA   Cattolico L., Weissenbach J., Saurin W., Quetier F., Schaefer M.,
RA   Mueller-Auer S., Gabel C., Fuchs M., Benes V., Wurmbach E., Drzonek H.,
RA   Erfle H., Jordan N., Bangert S., Wiedelmann R., Kranz H., Voss H.,
RA   Holland R., Brandt P., Nyakatura G., Vezzi A., D'Angelo M., Pallavicini A.,
RA   Toppo S., Simionati B., Conrad A., Hornischer K., Kauer G., Loehnert T.-H.,
RA   Nordsiek G., Reichelt J., Scharfe M., Schoen O., Bargues M., Terol J.,
RA   Climent J., Navarro P., Collado C., Perez-Perez A., Ottenwaelder B.,
RA   Duchemin D., Cooke R., Laudie M., Berger-Llauro C., Purnelle B., Masuy D.,
RA   de Haan M., Maarse A.C., Alcaraz J.-P., Cottet A., Casacuberta E.,
RA   Monfort A., Argiriou A., Flores M., Liguori R., Vitale D., Mannhaupt G.,
RA   Haase D., Schoof H., Rudd S., Zaccaria P., Mewes H.-W., Mayer K.F.X.,
RA   Kaul S., Town C.D., Koo H.L., Tallon L.J., Jenkins J., Rooney T., Rizzo M.,
RA   Walts A., Utterback T., Fujii C.Y., Shea T.P., Creasy T.H., Haas B.,
RA   Maiti R., Wu D., Peterson J., Van Aken S., Pai G., Militscher J.,
RA   Sellers P., Gill J.E., Feldblyum T.V., Preuss D., Lin X., Nierman W.C.,
RA   Salzberg S.L., White O., Venter J.C., Fraser C.M., Kaneko T., Nakamura Y.,
RA   Sato S., Kato T., Asamizu E., Sasamoto S., Kimura T., Idesawa K.,
RA   Kawashima K., Kishida Y., Kiyokawa C., Kohara M., Matsumoto M., Matsuno A.,
RA   Muraki A., Nakayama S., Nakazaki N., Shinpo S., Takeuchi C., Wada T.,
RA   Watanabe A., Yamada M., Yasuda M., Tabata S.;
RT   "Sequence and analysis of chromosome 3 of the plant Arabidopsis thaliana.";
RL   Nature 408:820-822(2000).
RN   [2]
RP   GENOME REANNOTATION.
RC   STRAIN=cv. Columbia;
RX   PubMed=27862469; DOI=10.1111/tpj.13415;
RA   Cheng C.Y., Krishnakumar V., Chan A.P., Thibaud-Nissen F., Schobel S.,
RA   Town C.D.;
RT   "Araport11: a complete reannotation of the Arabidopsis thaliana reference
RT   genome.";
RL   Plant J. 89:789-804(2017).
RN   [3]
RP   GENOME REANNOTATION.
RC   STRAIN=cv. Columbia;
RG   The Arabidopsis Information Resource (TAIR);
RT   "Community-consensus reference genome of Arabidopsis thaliana Col-0.";
RL   Submitted (FEB-2026) to the EMBL/GenBank/DDBJ databases.
RN   [4]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RC   STRAIN=cv. Columbia;
RX   PubMed=14593172; DOI=10.1126/science.1088305;
RA   Yamada K., Lim J., Dale J.M., Chen H., Shinn P., Palm C.J., Southwick A.M.,
RA   Wu H.C., Kim C.J., Nguyen M., Pham P.K., Cheuk R.F., Karlin-Newmann G.,
RA   Liu S.X., Lam B., Sakano H., Wu T., Yu G., Miranda M., Quach H.L.,
RA   Tripp M., Chang C.H., Lee J.M., Toriumi M.J., Chan M.M., Tang C.C.,
RA   Onodera C.S., Deng J.M., Akiyama K., Ansari Y., Arakawa T., Banh J.,
RA   Banno F., Bowser L., Brooks S.Y., Carninci P., Chao Q., Choy N., Enju A.,
RA   Goldsmith A.D., Gurjal M., Hansen N.F., Hayashizaki Y., Johnson-Hopson C.,
RA   Hsuan V.W., Iida K., Karnes M., Khan S., Koesema E., Ishida J., Jiang P.X.,
RA   Jones T., Kawai J., Kamiya A., Meyers C., Nakajima M., Narusaka M.,
RA   Seki M., Sakurai T., Satou M., Tamse R., Vaysberg M., Wallender E.K.,
RA   Wong C., Yamamura Y., Yuan S., Shinozaki K., Davis R.W., Theologis A.,
RA   Ecker J.R.;
RT   "Empirical analysis of transcriptional activity in the Arabidopsis
RT   genome.";
RL   Science 302:842-846(2003).
RN   [5]
RP   TISSUE SPECIFICITY.
RX   PubMed=17217470; DOI=10.1111/j.1365-313x.2006.02968.x;
RA   Roldan I., Wattebled F., Mercedes Lucas M., Delvalle D., Planchot V.,
RA   Jimenez S., Perez R., Ball S., D'Hulst C., Merida A.;
RT   "The phenotype of soluble starch synthase IV defective mutants of
RT   Arabidopsis thaliana suggests a novel function of elongation enzymes in the
RT   control of starch granule formation.";
RL   Plant J. 49:492-504(2007).
RN   [6]
RP   FUNCTION, AND DISRUPTION PHENOTYPE.
RC   STRAIN=cv. Columbia;
RX   PubMed=18811962; DOI=10.1186/1471-2229-8-96;
RA   Zhang X., Szydlowski N., Delvalle D., D'Hulst C., James M.G., Myers A.M.;
RT   "Overlapping functions of the starch synthases SSII and SSIII in
RT   amylopectin biosynthesis in Arabidopsis.";
RL   BMC Plant Biol. 8:96-96(2008).
RN   [7]
RP   IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
RX   PubMed=19376835; DOI=10.1104/pp.109.138677;
RA   Reiland S., Messerli G., Baerenfaller K., Gerrits B., Endler A.,
RA   Grossmann J., Gruissem W., Baginsky S.;
RT   "Large-scale Arabidopsis phosphoproteome profiling reveals novel
RT   chloroplast kinase substrates and phosphorylation networks.";
RL   Plant Physiol. 150:889-903(2009).
CC   -!- FUNCTION: Involved in the synthesis of glycan chains within amylopectin
CC       in leaves. Is required to produce chains with a degree of
CC       polymerization of 12 to 25 (DP12-DP25). {ECO:0000269|PubMed:18811962}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=[(1->4)-alpha-D-glucosyl](n) + ADP-alpha-D-glucose = [(1->4)-
CC         alpha-D-glucosyl](n+1) + ADP + H(+); Xref=Rhea:RHEA:18189, Rhea:RHEA-
CC         COMP:9584, Rhea:RHEA-COMP:9587, ChEBI:CHEBI:15378, ChEBI:CHEBI:15444,
CC         ChEBI:CHEBI:57498, ChEBI:CHEBI:456216; EC=2.4.1.21;
CC   -!- PATHWAY: Glycan biosynthesis; starch biosynthesis.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast. Plastid, amyloplast
CC       {ECO:0000305}.
CC   -!- TISSUE SPECIFICITY: Expressed in roots, leaves and flowers.
CC       {ECO:0000269|PubMed:17217470}.
CC   -!- DISRUPTION PHENOTYPE: Reduced plant growth under short day photopheriod
CC       conditions and starch granules with alterated morphology.
CC       {ECO:0000269|PubMed:18811962}.
CC   -!- SIMILARITY: Belongs to the glycosyltransferase 1 family.
CC       Bacterial/plant glycogen synthase subfamily. {ECO:0000305}.
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DR   EMBL; AC008261; AAF26156.1; -; Genomic_DNA.
DR   EMBL; CP002686; AEE73621.1; -; Genomic_DNA.
DR   EMBL; OZ408685; CAO7039212.1; -; Genomic_DNA.
DR   EMBL; AY054467; AAK96659.1; -; mRNA.
DR   EMBL; BT002555; AAO00915.1; -; mRNA.
DR   RefSeq; NP_186767.1; NM_110984.3.
DR   AlphaFoldDB; Q9MAC8; -.
DR   SMR; Q9MAC8; -.
DR   BioGRID; 5628; 11.
DR   FunCoup; Q9MAC8; 254.
DR   IntAct; Q9MAC8; 10.
DR   STRING; 3702.Q9MAC8; -.
DR   CAZy; GT5; Glycosyltransferase Family 5.
DR   iPTMnet; Q9MAC8; -.
DR   PaxDb; 3702-Q9MAC8; -.
DR   ProteomicsDB; 228258; -.
DR   GeneID; 820294; -.
DR   KEGG; ath:AT3G01180; -.
DR   Araport; AT3G01180; -.
DR   TAIR; AT3G01180; SS2.
DR   eggNOG; ENOG502QT35; Eukaryota.
DR   HOGENOM; CLU_009583_31_1_1; -.
DR   InParanoid; Q9MAC8; -.
DR   OMA; ACSFMFS; -.
DR   OrthoDB; 512920at2759; -.
DR   PhylomeDB; Q9MAC8; -.
DR   UniPathway; UPA00152; -.
DR   PRO; PR:Q9MAC8; -.
DR   Proteomes; UP000006548; Chromosome 3.
DR   Proteomes; UP001984100; Chromosome 3.
DR   ExpressionAtlas; Q9MAC8; baseline and differential.
DR   GO; GO:0009501; C:amyloplast; IEA:UniProtKB-SubCell.
DR   GO; GO:0009507; C:chloroplast; HDA:TAIR.
DR   GO; GO:0009011; F:alpha-1,4-glucan glucosyltransferase (ADP-glucose donor) activity; IMP:UniProtKB.
DR   GO; GO:0004373; F:alpha-1,4-glucan glucosyltransferase (UDP-glucose donor) activity; IEA:InterPro.
DR   GO; GO:0010021; P:amylopectin biosynthetic process; IMP:UniProtKB.
DR   GO; GO:0019252; P:starch biosynthetic process; IEA:UniProtKB-UniPathway.
DR   CDD; cd03791; GT5_Glycogen_synthase_DULL1-like; 1.
DR   FunFam; 3.40.50.2000:FF:000048; Starch synthase, chloroplastic/amyloplastic; 1.
DR   Gene3D; 3.40.50.2000; Glycogen Phosphorylase B; 2.
DR   HAMAP; MF_00484; Glycogen_synth; 1.
DR   InterPro; IPR011835; GS/SS.
DR   InterPro; IPR013534; Starch_synth_cat_dom.
DR   NCBIfam; TIGR02095; glgA; 1.
DR   PANTHER; PTHR45825; GRANULE-BOUND STARCH SYNTHASE 1, CHLOROPLASTIC/AMYLOPLASTIC; 1.
DR   PANTHER; PTHR45825:SF2; STARCH SYNTHASE 2, CHLOROPLASTIC_AMYLOPLASTIC; 1.
DR   Pfam; PF13692; Glyco_trans_1_4; 1.
DR   Pfam; PF08323; Glyco_transf_5; 1.
DR   SUPFAM; SSF53756; UDP-Glycosyltransferase/glycogen phosphorylase; 1.
PE   1: Evidence at protein level;
KW   Amyloplast; Chloroplast; Glycosyltransferase; Plastid; Reference proteome;
KW   Starch biosynthesis; Transferase; Transit peptide.
FT   TRANSIT         1..55
FT                   /note="Chloroplast"
FT                   /evidence="ECO:0000255"
FT   CHAIN           56..792
FT                   /note="Starch synthase 2, chloroplastic/amyloplastic"
FT                   /id="PRO_0000419769"
FT   REGION          105..295
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        145..156
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        179..192
FT                   /note="Low complexity"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        221..233
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        266..275
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   BINDING         315
FT                   /ligand="ADP-alpha-D-glucose"
FT                   /ligand_id="ChEBI:CHEBI:57498"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   792 AA;  87593 MW;  F8C852E4119EF670 CRC64;
     MASVAESSFP LLCQIKTQRR INSSTLRHSR VSYHDLPSGS LSFRSRSFVL GHRCKCVSRV
     EASGSDDDEP EDALQATIDK SKKVLAMQRN LLHQIAERRK LVSSIKESTP DLDDAKASSK
     QESASSVNAN TDATKKEIMD GDANGSVSPS TYGKSSLSKE PEAKTFSPST ESLKNRKQSS
     ASVISSSPVT SPQKPSDVAT NGKPWSSVVA SSVDPPYKPS SVMTSPEKTS DPVTSPGKPS
     KSRAGAFWSD PLPSYLTKAP QTSTMKTEKY VEKTPDVASS ETNEPGKDEE KPPPLAGANV
     MNVILVAAEC APFSKTGGLG DVAGALPKSL ARRGHRVMVV VPRYAEYAEA KDLGVRKRYK
     VAGQDMEVMY FHAFIDGVDF VFIDSPEFRH LSNNIYGGNR LDILKRMVLF CKAAVEVPWY
     VPCGGVCYGD GNLAFIANDW HTALLPVYLK AYYRDHGIMK YTRSVLVIHN IAHQGRGPVD
     DFSYVDLPSH YLDSFKLYDP VGGEHFNIFA AGLKAADRVL TVSHGYSWEV KTLEGGWGLH
     NIINENDWKF RGIVNGIDTQ EWNPEFDTYL HSDDYTNYSL ENLHIGKPQC KAALQKELGL
     PVRPDVPLIG FIGRLDHQKG VDLIAEAVPW MMSQDVQLVM LGTGRPDLEE VLRQMEHQYR
     DKARGWVGFS VKTAHRITAG ADILLMPSRF EPCGLNQLYA MNYGTIPVVH AVGGLRDTVQ
     QFDPYSETGL GWTFDSAEAG KLIHALGNCL LTYREYKESW EGLQRRGMTQ DLSWDNAAEK
     YEEVLVAAKY HW
//