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                specificity among alpha, beta, gamma

gamma subclasses
  I: 1,c,11 (farnesyl,C15)
 II: 2,3,4,7,12 (geranylgeranyl,C20)
III: 5,10 (geranylgeranyl,C20)

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alphao binds gamma2 > gamma1, mediated by Nterm 15 residues of gamma2;
  gamma2 prenylation required for association with alphao
  Rahmatullah et al. JBC 270(7):2946 (1995)
  Rahmatullah and Robishaw JBC 269(5):3574 (1994)

gamma carboxymethylation in beta1-gamma2, beta2-gamma3, and beta2-gamma7
  enhances interaction with alphai2, alphai3 (incr PTX modification) but not
  membrane localization   Rosenberg et al. Cellular Signalling 10:131 (1998)

gamma12 (unlike others) is a substrate of PKC; phosphorylation (probably at
  Ser1, maybe at Ser2) increases affinity for alphao,i2
  Morishita et al. JBC 270(49):29469 (1995)

yeast 2-hybrid reporter activity (probably should not interpret strictly
  quantitatively as relative affinities)
              beta1   beta2   beta3   beta4   beta5
    gamma1      4       3      <1      <1      <1
    gamma2      8       6       2       3       2
    gamma3     18      14       7       9      11
    gamma4     18      15       5       6      15
    gamma5     16      14       4       5       5
    gamma7     16      12       4       4       3
  Yan et al. JBC 271(12):7141 (1996)

              beta1   beta2   beta3
    gamma1      +       -       -  
    gamma2      +       +       -  
    gamma3      +       +       -  
    gamma4      +       +       -  
    gamma5      +       +       ND  
    gamma7      +       +       ND  
    gamma10     +       +       -  
    gamma11     +       -       -  
in vitro translation, biochemical assays (trypsin, gel filt, Xlink) gamma1,2
  Schmidt et al. JBC 267(20):13807 (1992)
colocalization of beta1,2,3 with CAAX-mutant gamma1,2
  Pronin and Gautam PNAS USA 89(13):6220 (1992)
in vitro translation, trypsin assay gamma 2,4,10,11 (previous work 3,5,7)
  Ray et al. JBC 270(37):21765 (1995)
combinations of purified beta1,2 with gamma 1,2,5,7 assayed for PTX
  modification of alphai1,o; inhibition of GTP hydrolysis by alphas,o,i2
  Ueda et al. JBC 269(6):4388 (1994)
combinations of beta1,2 with gamma 1,2,3 assayed for PTX modif of alphai1
  Iniguez-Lluhi et al. JBC 267(32):23409 (1992)

           beta1  beta2  beta3  beta3s  beta4  beta5  beta5L
  gamma1     +     (+)     -      -       +      -      -
  gamma2     +      +      +      -       +      -      -
  gamma3     +      +     (+)     -       +      -      -
  gamma4     +      +      -      -       +      -      -
  gamma5     +      +      -      -       +      -      -
  gamma7     +      +      -      -       +      -      -
  gamma8c    +      +      -      -       +      -      -
  gamma8o    +      +      -      -       +      -      -
  gamma10    +      +      -      -       +      -      -
  gamma11    +      -     (+)     -       +      -      -
  gamma12    +      +      +      -       +      -      -
  gamma13    +      -     (+)     -       +      -      -
in vitro translation, immunoprecipitation; contrasting results
in HEK293 cells: PLCbeta stim incr with beta5-gamma2/4/7/8o
  Dingus et al. Biochem 44:(35):11882 (2005)

beta4-gamma2 15x higher affinity for alphai1 than beta4-gamma11 although both
trimers are stable; beta4 may dissoc from gamma11 upon alpha activation
  McIntire et al. Biochemistry 45(38):11616 (2006)
 
gamma1 selectivity against beta2 due to gamma1 residues 38-40
     gamma1  EEF
     gamma2  ADL
  Lee et al. JBC 270(15):8779 (1995)
  previously localized to gamma1 36-49 (gamma2 33-46)
  Spring and Neer JBC 269(36):22882 (1994)

beta1 but not beta2 binds gamma1, mediated by 210-293 region of beta
  Katz and Simon PNAS USA 92:1998 (1995)
  previously implicated multiple regions within beta 215-302 (WD's 5-6)
  Garritsen and Simonds JBC 269(39):24418 (1994)

beta1-gamma2 association mediated by gamma2 Nterm 15-25 residues (extension
  of 12 residues allowed) and residues 45-59
  Mende et al. JBC 270(26):15892 (1995)

beta1-gamma2 association requires last 10 amino acids of beta1
  Yamauchi et al. Biochem Biophys Res Comm 214:694 (1995)

in bovine tissues, beta1 nonsel for gammas examined (2,3,5,12)
                   beta2 assoc gamma2,3,12 > 5
                   beta4 assoc gamma5 > 12 > 2 > 3
  Asano et al. JBC 274(30):21425 (1999)

in bovine brain, alphai1,i2,oA is with gamma2,3,7 > 5
                 alphaoB               gamma7 > 3 > 2
                 alphaoC               gamma5,3 > 2
  alphaoA,B,C are from same gene; splice variants B vs. A,C (thought to have
  same sequence but different posttranslational processing)
  Wilcox et al. JBC 270 (9):4189 (1995)

comparison of beta1 and beta5
  - beta1-gamma2 and beta2-gamma2 bind alphai1,i2,o,s,q
  - beta5-gamma2 only binds alphaq
  Fletcher et al. JBC 273(1):636 (1998)
  additional evidence Lindorfer et al JBC 273(5):34429 (1998)

beta5's physiological partners may be (instead of or as well as gamma2)
  C-subfamily RGS proteins which contain GGL (G-gamma-like) domains:
  RGS6,7,9,11 and EGL10
  Sondek and Siderovski Biochem Pharmacol 61:1329 (2001)

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