title: Gpn1 and Gpn3 associate tightly and their protein levels are mutually dependent in mammalian cells.
abstract: Gpn1 and Gpn3 are GTPases individually required for nuclear targeting of RNA polymerase II. Here we show that whereas Gpn3-EYFP distributed between the cytoplasm and cell nucleus, it was mainly cytoplasmic when coexpressed with Gpn1-Flag. Gpn3-Flag retained Gpn1-EYFP in the cytoplasm. However, Gpn3-EYFP/Gpn1-Flag nucleocytoplasmic shuttling was revealed after inhibiting nuclear export with leptomycin B. All Gpn3-EYFP coimmunoprecipitated with Gpn1-Flag, and all Gpn1-EYFP with Gpn3-Flag. Importantly, most endogenous Gpn1 and Gpn3 also associate. Gpn1-Gpn3 interaction was essential to maintain steady-state protein levels of both GTPases. We propose that most Gpn1 and Gpn3 associate, are mobilized, and function as a protein complex.
authors.affiliation: Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Universitaria, C.P. 78290 San Luis Potosí, San Luis Potosí, Mexico.
authors.forename: Lucía E
authors.initials: LE
authors.lastname: Méndez-Hernández
authors.affiliation: Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Universitaria, C.P. 78290 San Luis Potosí, San Luis Potosí, Mexico.
authors.forename: Ana E
authors.initials: AE
authors.lastname: Pérez-Mejía
authors.affiliation: Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Universitaria, C.P. 78290 San Luis Potosí, San Luis Potosí, Mexico.
authors.forename: Bárbara
authors.initials: B
authors.lastname: Lara-Chacón
authors.affiliation: Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Universitaria, C.P. 78290 San Luis Potosí, San Luis Potosí, Mexico.
authors.forename: Angel A
authors.initials: AA
authors.lastname: Barbosa-Camacho
authors.affiliation: Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Universitaria, C.P. 78290 San Luis Potosí, San Luis Potosí, Mexico.
authors.forename: Sonia G
authors.initials: SG
authors.lastname: Peña-Gómez
authors.affiliation: Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Universitaria, C.P. 78290 San Luis Potosí, San Luis Potosí, Mexico.
authors.forename: Mayra
authors.initials: M
authors.lastname: Martínez-Sánchez
authors.affiliation: Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Universitaria, C.P. 78290 San Luis Potosí, San Luis Potosí, Mexico.
authors.forename: Angélica Y
authors.initials: AY
authors.lastname: Robledo-Rivera
authors.affiliation: Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Universitaria, C.P. 78290 San Luis Potosí, San Luis Potosí, Mexico. Electronic address: rsanchez@ifisica.uaslp.mx.
authors.forename: Roberto
authors.initials: R
authors.lastname: Sánchez-Olea
authors.affiliation: Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Universitaria, C.P. 78290 San Luis Potosí, San Luis Potosí, Mexico. Electronic address: mcalera@ifisica.uaslp.mx.
authors.forename: Mónica R
authors.initials: MR
authors.lastname: Calera
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D011485:Protein Binding
chemical_list: D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; C472669:GPN1 protein, human; C562157:GPN3 protein, human
keywords: Gpn1; Gpn1–Gpn3 interaction; Gpn1–Gpn3 nucleocytoplasmic shuttling; Gpn3; Interdependent protein levels; shRNA