O48963 · PHOT1_ARATH

Function

function

Protein kinase that acts as a blue light (BL) photoreceptor in a signal-transduction pathway for photo-induced movements (PubMed:14739272, PubMed:15821287, PubMed:29101334, PubMed:31904040).
Triggers the phosphorylation of AHA1 and AHA2 C-terminal penultimate Thr in guard cells to activate them and induce stomatal opening in response to blue light (BL) (PubMed:15821287, PubMed:31904040).
Phosphorylates also BLUS1, a kinase involved in stomatal opening (PubMed:23811955).
Mediates the phosphorylation of CBC1 in stomata, but not of CBC2, in response to blue light (PubMed:29101334).
Required for blue light mediated mRNA destabilization. Mediates calcium spiking of extracellular origin in response to a low rate of blue light. Also mediates rapid membrane depolarization and growth inhibition in response to blue light. Necessary for root phototropism. Involved in hypocotyl phototropism under a low rate but not under a high rate of blue light. Contributes to the chloroplast accumulation but seems not to be required for chloroplast translocation. Regulates stomata opening and photomorphogenesis response of leaf tissue. Confers sensitivity to drought. Not involved in hypocotyl elongation inhibition, anthocyanin accumulation or cotyledon opening

Miscellaneous

Undergoes a photocycle characterized by fluorescence and absorption changes induced by blue light. Half-time of photoproduct formation is 14 seconds and 70 seconds for dark regeneration.

Catalytic activity

Cofactor

FMN (UniProtKB | Rhea| CHEBI:58210 )

Note: Binds 2 FMN per subunit.

Activity regulation

Autophosphorylation is inhibited by staurosporine, but not by tyrphostin 9, sphingosine, GW5074 and BML-265.

Absorption

Abs(max) = 450nm
Exhibits a smaller absorbance peak at 350 nm. The broad fluorescence emission spectrum peaks at 490 nm.

Features

Showing features for binding site, active site.

TypeIDPosition(s)Description
Binding site233FMN 1 (UniProtKB | ChEBI)
Binding site235FMN 1 (UniProtKB | ChEBI)
Binding site238FMN 1 (UniProtKB | ChEBI)
Binding site251FMN 1 (UniProtKB | ChEBI)
Binding site266FMN 1 (UniProtKB | ChEBI)
Binding site276FMN 1 (UniProtKB | ChEBI)
Binding site297FMN 1 (UniProtKB | ChEBI)
Binding site302FMN 1 (UniProtKB | ChEBI)
Binding site511FMN 2 (UniProtKB | ChEBI)
Binding site513FMN 2 (UniProtKB | ChEBI)
Binding site516FMN 2 (UniProtKB | ChEBI)
Binding site529FMN 2 (UniProtKB | ChEBI)
Binding site544FMN 2 (UniProtKB | ChEBI)
Binding site554FMN 2 (UniProtKB | ChEBI)
Binding site556FMN 2 (UniProtKB | ChEBI)
Binding site575FMN 2 (UniProtKB | ChEBI)
Binding site669-677ATP (UniProtKB | ChEBI)
Binding site692ATP (UniProtKB | ChEBI)
Active site788Proton acceptor

GO annotations

AspectTerm
Cellular Componentcell surface
Cellular Componentcytoplasm
Cellular Componentcytoplasmic side of plasma membrane
Cellular Componentplant-type vacuole
Molecular FunctionATP binding
Molecular Functionblue light photoreceptor activity
Molecular FunctionFMN binding
Molecular Functionidentical protein binding
Molecular Functionkinase activity
Molecular FunctionmRNA binding
Molecular Functionprotein kinase activity
Molecular Functionprotein serine kinase activity
Molecular Functionprotein serine/threonine kinase activity
Biological Processcellular response to blue light
Biological Processchloroplast accumulation movement
Biological Processchloroplast avoidance movement
Biological Processcircadian rhythm
Biological Processnegative regulation of anion channel activity by blue light
Biological Processphototropism
Biological Processprotein autophosphorylation
Biological Processregulation of proton transport
Biological Processregulation of stomatal movement
Biological Processresponse to blue light

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Phototropin-1
  • EC number
  • Alternative names
    • Non-phototropic hypocotyl protein 1
    • Root phototropism protein 1

Gene names

    • Name
      PHOT1
    • Synonyms
      JK224, NPH1
      , RPT1
    • ORF names
      T6D9_110
    • Ordered locus names
      At3g45780

Organism names

  • Taxonomic identifier
  • Strain
    • cv. Columbia
  • Taxonomic lineage
    Eukaryota > Viridiplantae > Streptophyta > Embryophyta > Tracheophyta > Spermatophyta > Magnoliopsida > eudicotyledons > Gunneridae > Pentapetalae > rosids > malvids > Brassicales > Brassicaceae > Camelineae > Arabidopsis

Accessions

  • Primary accession
    O48963

Proteomes

Organism-specific databases

Genome annotation databases

Subcellular Location

Phenotypes & Variants

Disruption phenotype

Enhanced drought tolerance, when associated with PHOT2 disruption (PubMed:20031924).
Plants lacking both PHOT1 and PHOT2 have curled downward leaves missing color changes in response to weak or strong blue light (BL) (PubMed:14739272, PubMed:31904040).
Impaired proton H+ pumping associated with altered increased ATP hydrolysis and absence of binding between 14-3-3 protein and H+-ATPase (e.g. AHA1 and AHA2) in response to BL in guard cells of plants missing PHOT1 and PHOT2 (PubMed:15821287).

Features

Showing features for mutagenesis.

TypeIDPosition(s)Description
Mutagenesis234No effect on the kinase activity regulation.
Mutagenesis512Loss of light-sensing and light-dependent autophosphorylation.
Mutagenesis774In nph1-1; loss of phototropism.
Mutagenesis806Lost kinase activity, unable to phosphorylate CBC1.
Mutagenesis936In nph1-2; partial phototropism.

Variants

We now provide the "Disease & Variants" viewer in its own tab.

The viewer provides 85 variants from UniProt as well as other sources including ClinVar and dbSNP.

Go to variant viewer

PTM/Processing

Features

Showing features for chain, modified residue, disulfide bond.

TypeIDPosition(s)Description
ChainPRO_00000865221-996Phototropin-1
Modified residue23Phosphoserine
Modified residue58Phosphoserine
Modified residue185Phosphoserine
Modified residue234S-4a-FMN cysteine
Disulfide bond261Interchain
Modified residue350Phosphoserine
Modified residue376Phosphoserine
Modified residue410Phosphoserine
Modified residue450Phosphoserine
Modified residue512S-4a-FMN cysteine

Post-translational modification

Autophosphorylated at Ser-185, Ser-350 and Ser-410 in response to blue light irradiation.
2 molecules of FMN bind covalently to cysteines after exposure to blue light and are reversed in the dark.

Keywords

Proteomic databases

PTM databases

Expression

Tissue specificity

Present in guard cells (at protein level).

Gene expression databases

Interaction

Subunit

Homodimer; disulfide-linked (PubMed:18585389, PubMed:24316821).
Interacts with PKS1, PKS2, RPT2, RPT3, PHOT2 and BLUS1 (PubMed:10542152, PubMed:15031408, PubMed:16777956, PubMed:18585389, PubMed:20071603, PubMed:23811955).
Subunit of a complex made of CAR6, PHOT1 and RPT3/NPH3 (PubMed:21367967).
Associates with CBC1 and CBC2 (PubMed:31904040).
Binds to BHP (PubMed:28358053).

Binary interactions

Protein-protein interaction databases

Family & Domains

Features

Showing features for compositional bias, region, domain.

TypeIDPosition(s)Description
Compositional bias1-37Polar residues
Region1-184Disordered
Compositional bias133-168Polar residues
Domain184-257PAS 1
Domain258-312PAC 1
Region351-413Disordered
Compositional bias380-394Polar residues
Region434-453Disordered
Domain462-535PAS 2
Domain536-590PAC 2
Domain663-952Protein kinase
Region806-862Activation loop

Domain

The activation loop within the kinase domain is the target of phosphorylation (By similarity).
The PAS (PER-ARNT-SIM) domains are required for the binding of FMN chromophores (Probable)

Sequence similarities

Keywords

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    996
  • Mass (Da)
    111,689
  • Last updated
    1998-06-01 v1
  • Checksum
    C9B68812F1B3A04E
MEPTEKPSTKPSSRTLPRDTRGSLEVFNPSTQLTRPDNPVFRPEPPAWQNLSDPRGTSPQPRPQQEPAPSNPVRSDQEIAVTTSWMALKDPSPETISKKTITAEKPQKSAVAAEQRAAEWGLVLKTDTKTGKPQGVGVRNSGGTENDPNGKKTTSQRNSQNSCRSSGEMSDGDVPGGRSGIPRVSEDLKDALSTFQQTFVVSDATKPDYPIMYASAGFFNMTGYTSKEVVGRNCRFLQGSGTDADELAKIRETLAAGNNYCGRILNYKKDGTSFWNLLTIAPIKDESGKVLKFIGMQVEVSKHTEGAKEKALRPNGLPESLIRYDARQKDMATNSVTELVEAVKRPRALSESTNLHPFMTKSESDELPKKPARRMSENVVPSGRRNSGGGRRNSMQRINEIPEKKSRKSSLSFMGIKKKSESLDESIDDGFIEYGEEDDEISDRDERPESVDDKVRQKEMRKGIDLATTLERIEKNFVITDPRLPDNPIIFASDSFLELTEYSREEILGRNCRFLQGPETDLTTVKKIRNAIDNQTEVTVQLINYTKSGKKFWNIFHLQPMRDQKGEVQYFIGVQLDGSKHVEPVRNVIEETAVKEGEDLVKKTAVNIDEAVRELPDANMTPEDLWANHSKVVHCKPHRKDSPPWIAIQKVLESGEPIGLKHFKPVKPLGSGDTGSVHLVELVGTDQLFAMKAMDKAVMLNRNKVHRARAEREILDLLDHPFLPALYASFQTKTHICLITDYYPGGELFMLLDRQPRKVLKEDAVRFYAAQVVVALEYLHCQGIIYRDLKPENVLIQGNGDISLSDFDLSCLTSCKPQLLIPSIDEKKKKKQQKSQQTPIFMAEPMRASNSFVGTEEYIAPEIISGAGHTSAVDWWALGILMYEMLYGYTPFRGKTRQKTFTNVLQKDLKFPASIPASLQVKQLIFRLLQRDPKKRLGCFEGANEVKQHSFFKGINWALIRCTNPPELETPIFSGEAENGEKVVDPELEDLQTNVF

Features

Showing features for compositional bias.

TypeIDPosition(s)Description
Compositional bias1-37Polar residues
Compositional bias133-168Polar residues
Compositional bias380-394Polar residues

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AF030864
EMBL· GenBank· DDBJ
AAC01753.1
EMBL· GenBank· DDBJ
mRNA
AL157735
EMBL· GenBank· DDBJ
CAB75791.1
EMBL· GenBank· DDBJ
Genomic DNA
CP002686
EMBL· GenBank· DDBJ
AEE78072.1
EMBL· GenBank· DDBJ
Genomic DNA
CP002686
EMBL· GenBank· DDBJ
AEE78073.1
EMBL· GenBank· DDBJ
Genomic DNA
AF360218
EMBL· GenBank· DDBJ
AAK25928.1
EMBL· GenBank· DDBJ
mRNA
AY040062
EMBL· GenBank· DDBJ
AAK64120.1
EMBL· GenBank· DDBJ
mRNA

Genome annotation databases

Similar Proteins

Disclaimer

Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care. Our staff consists of biologists and biochemists that are not trained to give medical advice.
We'd like to inform you that we have updated our Privacy Notice to comply with Europe’s new General Data Protection Regulation (GDPR) that applies since 25 May 2018.
FeedbackHelp