title: Rap2 function requires palmitoylation and recycling endosome localization.
abstract: Rap2A, Rap2B, and Rap2C are Ras-like small G proteins. The role of their post-translational processing has not been investigated due to the lack of information on their downstream signaling. We have recently identified the Traf2- and Nck-interacting kinase (TNIK), a member of the STE20 group of mitogen-activated protein kinase kinase kinase kinases, as a specific Rap2 effector. Here we report that, in HEK293T cells, Rap2A (farnesylated) and Rap2C (likely farnesylated), but not Rap2B (geranylgeranylated), require palmitoylation for membrane-association and TNIK activation, whereas all Rap2 proteins, including Rap2B, require palmitoylation for induction of TNIK-mediated phenotype, the suppression of cell spreading. Furthermore, we report for the first time that, in COS-1 cells, Rap2 proteins localize, and recruit TNIK, to the recycling endosomes, but not the Golgi nor the endoplasmic reticulum, in a palmitoylation-dependent manner. These observations implicate the involvement of palmitoylation and recycling endosome localization in cellular functions of Rap2 proteins.
authors.affiliation: Division of Cell Biology, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Uechi
authors.forename: Maitsetseg
authors.initials: M
authors.lastname: Bayarjargal
authors.forename: Masato
authors.initials: M
authors.lastname: Umikawa
authors.forename: Minoru
authors.initials: M
authors.lastname: Oshiro
authors.forename: Kimiko
authors.initials: K
authors.lastname: Takei
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Yamashiro
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Asato
authors.forename: Shogo
authors.initials: S
authors.lastname: Endo
authors.forename: Ryo
authors.initials: R
authors.lastname: Misaki
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Taguchi
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Kariya
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D004721:Endoplasmic Reticulum / Q000201:enzymology; D011992:Endosomes / Q000201:enzymology*; D004789:Enzyme Activation; D000081410:Germinal Center Kinases; D006056:Golgi Apparatus / Q000201:enzymology; D006801:Humans; D054878:Lipoylation; D008969:Molecular Sequence Data; D010641:Phenotype; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D020668:rap GTP-Binding Proteins / Q000378:metabolism*; D018631:ras Proteins / Q000378:metabolism*
chemical_list: D000081410:Germinal Center Kinases; D017346:Protein Serine-Threonine Kinases; C000631454:TNIK protein, human; C116756:RAP2A protein, human; C065562:RAP2B protein, human; C511733:Rap2C protein, human; D020668:rap GTP-Binding Proteins; D018631:ras Proteins