>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=99.26 E-value=1e-10 Score=89.62 Aligned_cols=162 Identities=18% Similarity=0.217 Sum_probs=103.3 Q ss_pred CCCCEEEEECCCCCCHHHHHHHHHHHCCCCCCCCCCCCEECCCCHHHHHCCCEEEEEEEEEEECCEEEEEECCCCCCCCH Q ss_conf 24314999854689877889999998396142322000003885779870960646799999899799997289875407 Q gi|254780233|r 17 MQIRNIAIIAHVDHGKTTLVDELLKQSGVFRDNQRVSERVMDCNDLEKERGITILAKVTSIVWNDVRINIVDTPGHADFG 96 (624) Q Consensus 17 ~~IRNiaIiaHvDhGKTTL~d~LL~~sG~~~~~~~v~~~vmD~~~~EreRGITI~a~~~~~~~~~~~iNiiDTPGH~DF~ 96 (624) T Consensus 17 ~k~~kIlilGld~aGKTTil~~l~--~~~------~~~----~~-------PT~Gfn~e~i~~~~~~~~~wDvgG~~~~R 77 (190) T cd00879 17 NKEAKILFLGLDNAGKTTLLHMLK--DDR------LAQ----HV-------PTLHPTSEELTIGNIKFKTFDLGGHEQAR 77 (190) T ss_pred CCCCEEEEEECCCCCHHHHHHHHH--CCC------CCE----EC-------CCCCCCEEEEEECCEEEEEEECCCCCCCC T ss_conf 770489999069998899999980--799------531----52-------65587459999899999999899984555 Q ss_pred HHHHHHHHHHCEEEEEEECCCC-CCHHHHHHHHHHH----HCCCCEEEEEECCCCCCCCHHHHHHHHHHHHHHCCCC--- Q ss_conf 9999998742178999976878-8647899999999----7299789999754366740256899999888622673--- Q gi|254780233|r 97 GEVERILCMVESVVVLVDAAEG-PMPQTKFVVGKAL----KIGLRPIVVVNKVDRSDARADEVINEVFDLFSALDAT--- 168 (624) Q Consensus 97 gEVer~l~~~DgaiLvVdA~eG-v~~QT~~vl~~A~----~~~l~~IvvINKiDr~~a~~~~v~~ei~dlf~~l~a~--- 168 (624) T Consensus 78 ~lW~~Y~~~~~~iIfVVDssD~~r~~eak~~L~~lL~~~~l~~~PlLIlaNK~Dl~~a~~~~ei~~~L~L~~~~~~~~~~ 157 (190) T cd00879 78 RLWKDYFPEVDGIVFLVDAADPERFQESKEELDSLLSDEELANVPFLILGNKIDLPGAVSEEELRQALGLYGTTTGKGVS 157 (190) T ss_pred CCHHHHHHCCCEEEEEEECCCHHHHHHHHHHHHHHHHHHHHCCCCEEEEEECCCCCCCCCHHHHHHHCCCCCCCCCCCCC T ss_conf 43888843113799999776778999999999999855500698089998666776798999999883984201554433 Q ss_pred ---HHHCCHHHHHHHHHCCEECCCCCCCCCCCCHHHHHHHHCC Q ss_conf ---0110426688788659164674223348641355532102 Q gi|254780233|r 169 ---DAQLDFPILYGSGRFGWMSDSSDGSRDQGMVPLLNLIVDH 208 (624) Q Consensus 169 ---de~ld~Pv~~~Sa~~G~~~~~~~~~~~~gl~~Lld~Ii~~ 208 (624) T Consensus 158 ~~~~~~r~~~i~~csA~tG-----------~Gl~egl~WLs~~ 189 (190) T cd00879 158 LKVSGIRPIEVFMCSVVKR-----------QGYGEAFRWLSQY 189 (190) T ss_pred CCCCCCCCEEEEEEEEECC-----------CCHHHHHHHHHHH T ss_conf 4545776149996550679-----------6828999999854

HHsearch alignment for GI: 254780233 and conserved domain: cd00879