title: Regulation of cytokine-inducible SH2-containing protein (CIS) by ubiquitination and Elongin B/C interaction.
abstract: Cytokine-inducible SH2-containing protein (CIS) inhibits prolactin receptor (PRLR) signaling and acts as part of an E3 ubiquitin ligase complex through interactions with Elongin B/C proteins. This study aimed to identify CIS lysine ubiquitination sites and determine roles of ubiquitination and Elongin B/C interactions on CIS protein stability and PRLR signaling inhibition. Site-directed mutations revealed that CIS can be ubiquitinated on all six lysine residues. Elongin B/C interaction box mutation had no influence on CIS ubiquitination. CIS stability was increased by mutation of lysine residues and further enhanced by co-mutation of Elongin B/C interaction domain. CIS inhibition of STAT5B phosphorylation and casein promoter activation was dependent on CIS interactions with Elongin B/C, but not on CIS ubiquitination. These data indicate CIS protein stability is regulated through multiple mechanisms, including ubiquitination and interaction with Elongin B/C proteins, whereas CIS functional inhibition of PRLR signaling is dependent on the Elongin B/C interaction.
authors.affiliation: Department of Physiology, Southern Illinois University School of Medicine, 1135 Lincoln Drive, Carbondale, IL 62901-6523, USA.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Jensik
authors.affiliation: Department of Physiology, Southern Illinois University School of Medicine, 1135 Lincoln Drive, Carbondale, IL 62901-6523, USA. Electronic address: larbogast@siumed.edu.
authors.forename: Lydia A
authors.initials: LA
authors.lastname: Arbogast
mesh_terms: D002364:Caseins / Q000235:genetics; D000075065:Elongin; D057809:HEK293 Cells; D006801:Humans; D008239:Lysine / Q000235:genetics*; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D055550:Protein Stability; D011981:Receptors, Prolactin / Q000378:metabolism*; D050799:STAT5 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction; D050826:Suppressor of Cytokine Signaling Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D002364:Caseins; D000075065:Elongin; D008239:Lysine; D011981:Receptors, Prolactin; D050799:STAT5 Transcription Factor; D050826:Suppressor of Cytokine Signaling Proteins; D014157:Transcription Factors; C000616396:ELOB protein, human; C494095:STAT5B protein, human
keywords: CIS; Prolactin receptor; Protein degradation; STAT5; Signal transduction; Ubiquitination