title: Arg188 drives RhoC membrane binding.
abstract: RhoA and RhoC GTPases are 92% identical but demonstrate unique regulation and function. Phosphorylation of Ser188 has widely been reported to inhibit RhoA activity. RhoC possesses Arg188 in place of Ser188 but retains a canonical upstream PKA recognition sequence. We report here that RhoC-R188S was a PKA substrate in vitro and exhibited less GTP loading compared to wild-type RhoC when expressed in cells. Transiently expressed RhoC was found to be significantly more membrane associated than RhoA. Membrane association of RhoC-R188S and RhoC-R188A were similar to each other and wild-type RhoA, suggesting that Arg188 directly promotes RhoC membrane binding. The positive influence of Arg188 on RhoC membrane association was evident in a constitutively active (Q63L) background. In accordance, RhoA-S188R was significantly more membrane associated than either RhoA or RhoA-S188A. Altogether, these data suggest that swapping residue 188 identity effectively flips the membrane binding profile of wild-type RhoA and RhoC through positive arginine contribution rather than negative phosphoserine regulation.
authors.affiliation: a Department of BCES , Wartburg College , Waverly , IA , USA.
authors.forename: Aditi
authors.initials: A
authors.lastname: Patel
authors.affiliation: a Department of BCES , Wartburg College , Waverly , IA , USA.
authors.forename: Sophia
authors.initials: S
authors.lastname: Williams-Perez
authors.affiliation: a Department of BCES , Wartburg College , Waverly , IA , USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Peyton
authors.affiliation: a Department of BCES , Wartburg College , Waverly , IA , USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Reicks
authors.affiliation: a Department of BCES , Wartburg College , Waverly , IA , USA.
authors.forename: Justin
authors.initials: J
authors.lastname: Buzick
authors.affiliation: a Department of BCES , Wartburg College , Waverly , IA , USA.
authors.forename: Janean
authors.initials: J
authors.lastname: Farley
authors.affiliation: a Department of BCES , Wartburg College , Waverly , IA , USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Shirar
authors.affiliation: a Department of BCES , Wartburg College , Waverly , IA , USA.
authors.forename: Shawn M
authors.initials: SM
authors.lastname: Ellerbroek
mesh_terms: D001120:Arginine / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D006801:Humans; D009154:Mutation; D011485:Protein Binding; D000075024:rhoC GTP-Binding Protein / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D001120:Arginine; D000075024:rhoC GTP-Binding Protein
keywords: RhoA; RhoC; arginine; membrane; serine