>cd00879 Sar1 Sar1 subfamily. 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.

Probab=98.86 E-value=4e-08 Score=70.89 Aligned_cols=125 Identities=22% Similarity=0.235 Sum_probs=86.0 Q ss_pred HHEEEEEEECCCCCCHHHHHHHHHHHCCCCCCCCEECCCCEECCCHHHHHHHCCCEEEEEEEEEECCCCCCCEEEEEEEC Q ss_conf 02527999868788977899999998087321422017956137808898708537640799996077787138999817 Q gi|254780264|r 8 EDSRNFGIMAHIDAGKTTTTERILYYAGKSHKIGEVHDGSATMDWMEQEQERGITITSASTTVFWPGRDGGQKKLTIIDT 87 (701) Q Consensus 8 e~iRNv~iiaHvd~GKTTL~d~LL~~~g~i~~~g~v~~g~~~~D~~~~E~eRgITi~ss~~sl~~~~~~~~~~~iNlIDT 87 (701) T Consensus 17 ~k~~kIlilGld~aGKTTil~~l~--~~~~~~---------~~----------PT~Gfn~e~i~~~-----~~~~~~wDv 70 (190) T cd00879 17 NKEAKILFLGLDNAGKTTLLHMLK--DDRLAQ---------HV----------PTLHPTSEELTIG-----NIKFKTFDL 70 (190) T ss_pred CCCCEEEEEECCCCCHHHHHHHHH--CCCCCE---------EC----------CCCCCCEEEEEEC-----CEEEEEEEC T ss_conf 770489999069998899999980--799531---------52----------6558745999989-----999999989 Q ss_pred CCCCCCHHHHHHHHHHHCEEEEEEECCCCC-CHHHHH----HHHHHHHCCCCEEEEECCCCCCCCCHHHHHHHHCCCCC Q ss_conf 987552899999998604569999558888-834799----99999873997899981767658755556664111102 Q gi|254780264|r 88 PGHVDFTMEVERSIRVTDGAIALLDSNAGV-EPQTET----VWRQADKYSVPRVIFCNKMDKMGADFYRSVEMISSRLG 161 (701) Q Consensus 88 PGH~DF~~Ev~~aL~~~DgailvVDa~eGv-~~qT~~----vlr~~~~~~lp~ilvINKiDr~~~d~~~~l~~i~~~l~ 161 (701) T Consensus 71 gG~~~~R~lW~~Y~~~~~~iIfVVDssD~~r~~eak~~L~~lL~~~~l~~~PlLIlaNK~Dl~~a---~~~~ei~~~L~ 146 (190) T cd00879 71 GGHEQARRLWKDYFPEVDGIVFLVDAADPERFQESKEELDSLLSDEELANVPFLILGNKIDLPGA---VSEEELRQALG 146 (190) T ss_pred CCCCCCCCCHHHHHHCCCEEEEEEECCCHHHHHHHHHHHHHHHHHHHHCCCCEEEEEECCCCCCC---CCHHHHHHHCC T ss_conf 99845554388884311379999977677899999999999985550069808999866677679---89999998839

HHsearch alignment for GI: 254780264 and conserved domain: cd00879