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  Domain Name: Sar1
Sar1 is an essential component of COPII vesicle coats. Sar1 is an essential component of COPII vesicle coats involved in export of cargo from the ER. The GTPase activity of Sar1 functions as a molecular switch to control protein-protein and protein-lipid interactions that direct vesicle budding from the ER. Activation of the GDP to the GTP-bound form of Sar1 involves the membrane-associated guanine nucleotide exchange factor (GEF) Sec12. Sar1 is unlike all Ras superfamily GTPases that use either myristoyl or prenyl groups to direct membrane association and function, in that Sar1 lacks such modification. Instead, Sar1 contains a unique nine-amino-acid N-terminal extension. This extension contains an evolutionarily conserved cluster of bulky hydrophobic amino acids, referred to as the Sar1-N-terminal activation recruitment (STAR) motif. The STAR motif mediates the recruitment of Sar1 to ER membranes and facilitates its interaction with mammalian Sec12 GEF leading to activation.
No pairwise interactions are available for this conserved domain.

Total Mutations Found: 14
Total Disease Mutations Found: 1
This domain occurred 34 times on human genes (49 proteins).


 If you've navigated here from a protein, hovering over a position on the weblogo will display the corresponding protein position for that domain position.

 The histograms below the weblogo indicate mutations found on the domain. Red is for disease (OMIM) and blue is for SNPs.

 Functional Features are displayed as orange boxes under the histograms. You can choose which features are displayed in the box below.

Range on the Protein:  

   Protein ID            Protein Position

Domain Position:  

Feature Name:Total Found:
GTP/Mg2+ binding site
GAP interaction site
putative effector interac
putative GEF interaction
Switch I region
Switch II region
interswitch region
G1 box
G2 box
G3 box
G4 box
G5 box
STAR motif

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Please Cite: Peterson, T.A., Adadey, A., Santana-Cruz ,I., Sun, Y., Winder A, Kann, M.G., (2010) DMDM: Domain Mapping of Disease Mutations. Bioinformatics 26 (19), 2458-2459.

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