>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=99.44 E-value=2e-12 Score=90.53 Aligned_cols=158 Identities=22% Similarity=0.241 Sum_probs=91.8 Q ss_pred CCEEEEECCCCCCHHHHHHHHHCCCCEEEECCCCCEEEECCEEEEEEEEEEEECCCEEEEEECCHHHHHHHHHHHHHHHH Q ss_conf 86899974899889899999738973798738884145212026655567850896499997600101112244789888 Q gi|254780484|r 29 PPEIAFSGRSNVGKSSLINILVNRKNLARTSNAPGRTQHLNFFVPKDFSNLKNNLPAMALVDMPGYGYARAPKKNVDSWG 108 (212) Q Consensus 29 ~p~VaivG~~NvGKSSLiNaL~g~~~~a~~~~~p~tt~~~~~~~~~~~~~~~~~~~~~~~~DtpG~~~~~~~~~~~~~~~ 108 (212) T Consensus 19 ~~kIlilGld~aGKTTil~~l~~~~~-~~~--~PT--~Gfn------~e~i~~~~~~~~~wDvgG~~~~R~l------W~ 81 (190) T cd00879 19 EAKILFLGLDNAGKTTLLHMLKDDRL-AQH--VPT--LHPT------SEELTIGNIKFKTFDLGGHEQARRL------WK 81 (190) T ss_pred CCEEEEEECCCCCHHHHHHHHHCCCC-CEE--CCC--CCCC------EEEEEECCEEEEEEECCCCCCCCCC------HH T ss_conf 04899990699988999999807995-315--265--5874------5999989999999989998455543------88 Q ss_pred HHHHHHHHHHHHHCCCCCCCCCCCCCCHH-----HHHHHHHHCCCCCCCCCCCCCCCCCCHHHHHHHHHHHH--HHHHHC Q ss_conf 89987777664200000112235788754-----54554321025753221222211110246899999999--997531 Q gi|254780484|r 109 GLIVRYLSERSTLRCVYLLIDCRHGVKQI-----DQDVFSFLDKKAVSYQIVLTKIDKLSPTTAQETLEKTK--YLIRNY 181 (212) Q Consensus 109 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~-----~~~~~~~~~~~~~~~~~v~nK~D~~~~~~~~~~~~~~~--~~~~~~ 181 (212) T Consensus 82 ~----Y---~~~~~~iIfVVDssD~~r~~eak~~L~~lL~~~~l~~~PlLIlaNK~Dl~~a~~~~ei~~~L~L~~~~~~~ 154 (190) T cd00879 82 D----Y---FPEVDGIVFLVDAADPERFQESKEELDSLLSDEELANVPFLILGNKIDLPGAVSEEELRQALGLYGTTTGK 154 (190) T ss_pred H----H---HHCCCEEEEEEECCCHHHHHHHHHHHHHHHHHHHHCCCCEEEEEECCCCCCCCCHHHHHHHCCCCCCCCCC T ss_conf 8----8---43113799999776778999999999999855500698089998666776798999999883984201554 Q ss_pred -------CCCCCCEEEEECCCCCCHHHHHHHHHHHH Q ss_conf -------36898689998888899899999999872 Q gi|254780484|r 182 -------PTAHPEVIPTSSVKRKGIEVLRKAILETI 210 (212) Q Consensus 182 -------~~~~~~i~~vSA~~g~Gi~eL~~~I~~~l 210 (212) T Consensus 155 ~~~~~~~~~r~~~i~~csA~tG~Gl~egl~WLs~~l 190 (190) T cd00879 155 GVSLKVSGIRPIEVFMCSVVKRQGYGEAFRWLSQYL 190 (190) T ss_pred CCCCCCCCCCCEEEEEEEEECCCCHHHHHHHHHHHC T ss_conf 433454577614999655067968289999998549

HHsearch alignment for GI: 254780484 and conserved domain: cd00879