O04267 · SAR1B_BRACM

Function

function

Small GTPase that cycles between an active GTP-bound and an inactive GDP-bound state and mainly functions in vesicle-mediated endoplasmic reticulum (ER) to Golgi transport. The active GTP-bound form inserts into the endoplasmic reticulum membrane where it recruits the remainder of the coat protein complex II/COPII. The coat protein complex II assembling and polymerizing on endoplasmic reticulum membrane is responsible for both the sorting of cargos and the deformation and budding of membranes into vesicles destined to the Golgi.

Catalytic activity

Activity regulation

Small GTPases activation is mediated by guanine exchange factors (GEF), while inactivation through hydrolysis of the bound GTP is stimulated by GTPase activating proteins (GAP).

Features

Showing features for binding site.

TypeIDPosition(s)Description
Binding site29Mg2+ (UniProtKB | ChEBI)
Binding site30GDP (UniProtKB | ChEBI)
Binding site30GTP (UniProtKB | ChEBI)
Binding site31GDP (UniProtKB | ChEBI)
Binding site32GDP (UniProtKB | ChEBI)
Binding site32GTP (UniProtKB | ChEBI)
Binding site33GDP (UniProtKB | ChEBI)
Binding site33GTP (UniProtKB | ChEBI)
Binding site34GDP (UniProtKB | ChEBI)
Binding site34GTP (UniProtKB | ChEBI)
Binding site35GDP (UniProtKB | ChEBI)
Binding site35GTP (UniProtKB | ChEBI)
Binding site53GDP (UniProtKB | ChEBI)
Binding site70Mg2+ (UniProtKB | ChEBI)
Binding site129GDP (UniProtKB | ChEBI)
Binding site129GTP (UniProtKB | ChEBI)
Binding site130GDP (UniProtKB | ChEBI)
Binding site130GTP (UniProtKB | ChEBI)
Binding site132GDP (UniProtKB | ChEBI)
Binding site132GTP (UniProtKB | ChEBI)
Binding site177GDP (UniProtKB | ChEBI)
Binding site177GTP (UniProtKB | ChEBI)

GO annotations

AspectTerm
Cellular Componentendoplasmic reticulum membrane
Cellular ComponentGolgi cisterna membrane
Molecular FunctionGTP binding
Molecular FunctionGTPase activity
Molecular Functionmetal ion binding
Biological Processintracellular protein transport
Biological Processvesicle-mediated transport

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Small COPII coat GTPase SAR1B
  • EC number
  • Alternative names
    • GTP-binding protein SAR1B

Gene names

    • Name
      SAR1B

Organism names

  • Taxonomic identifier
  • Taxonomic lineage
    Eukaryota > Viridiplantae > Streptophyta > Embryophyta > Tracheophyta > Spermatophyta > Magnoliopsida > eudicotyledons > Gunneridae > Pentapetalae > rosids > malvids > Brassicales > Brassicaceae > Brassiceae > Brassica

Accessions

  • Primary accession
    O04267

Proteomes

Subcellular Location

Endoplasmic reticulum membrane
; Peripheral membrane protein
Golgi apparatus, Golgi stack membrane
; Peripheral membrane protein
Note: Active at endoplasmic reticulum exit sites (ERES) where it inserts into the membrane and recruits the remainder of the coat protein complex II/COPII.

Keywords

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00002062681-195Small COPII coat GTPase SAR1B

Expression

Tissue specificity

Expressed in most tissues.

Interaction

Subunit

Homodimer; upon association with membrane. Part of the coat protein complex II/COPII, composed of SEC23/24 and SEC13/31 heterodimers, that it helps recruit and assemble on endoplasmic reticulum (ER) membranes at ER exit site.

Structure

Family & Domains

Features

Showing features for motif, region.

TypeIDPosition(s)Description
Motif2-4STAR; SAR1-N-terminal activation recruitment. Required for the activation and subsequent recruitment to ER membrane
Region10-14Mediates recruitment to ER membranes

Sequence similarities

Belongs to the small GTPase superfamily. SAR1 family.

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    195
  • Mass (Da)
    22,077
  • Last updated
    1997-07-01 v1
  • Checksum
    A2FC46B348F29D7B
MFLFDWFYGILASLGLWQKEAKILFLGLDNAGKTTLLHMLKDERLVQHQPTQHPTSEELSIGKIKFKAFDLGGHQIARRVWKDYYAKVDAVVYLVDAYDKERFSESKKELDALLSDDALATVPFLILGNKIDNPYAASEDELRYHLGLTNFTTGKGKVTTAGGDSGVRPLEVFMCSIVRKMGYGEGFKWLSQYIN

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
U55036
EMBL· GenBank· DDBJ
AAC49717.1
EMBL· GenBank· DDBJ
mRNA

Similar Proteins

Disclaimer

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