title: The ubiquitin E3 ligase SCF-FBXO24 recognizes deacetylated nucleoside diphosphate kinase A to enhance its degradation.
abstract: The Skp-Cul-F box (SCF) ubiquitin E3 ligase machinery recognizes predominantly phosphodegrons or, less commonly, an (I/L)Q molecular signature within substrates to facilitate their recruitment in mediating protein ubiquitination and degradation. Here, we examined the molecular signals that determine the turnover of the multifunctional enzyme nucleoside diphosphate kinase A (NDPK-A) that controls cell proliferation. NDPK-A protein exhibits a half-life of ∼6 h in HeLa cells and is targeted for ubiquitylation through actions of the F-box protein FBXO24. SCF-FBXO24 polyubiquitinates NDPK-A at K85, and two NH(2)-terminal residues, L55 and K56, were identified as important molecular sites for FBXO24 interaction. Importantly, K56 acetylation impairs its interaction with FBXO24, and replacing K56 with Q56, an acetylation mimic, reduces NDPK-A FBXO24 binding capacity. The acetyltransferase GCN5 catalyzes K56 acetylation within NDPK-A, thereby stabilizing NDPK-A, whereas GCN5 depletion in cells accelerates NDPK-A degradation. Cellular expression of an NDPK-A acetylation mimic or FBXO24 silencing increases NDPK-A life span which, in turn, impairs cell migration and wound healing. We propose that lysine acetylation when presented in the appropriate context may be recognized by some F-box proteins as a unique inhibitory molecular signal for their recruitment to restrict substrate degradation.
authors.affiliation: Institute of Biomedicine and National Engineering Research Center of Genetic Medicine, College of Life Science and Technology, Jinan University, Guangzhou, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: Institute of Biomedicine and National Engineering Research Center of Genetic Medicine, College of Life Science and Technology, Jinan University, Guangzhou, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Xiong
authors.affiliation: Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.affiliation: Institute of Biomedicine and National Engineering Research Center of Genetic Medicine, College of Life Science and Technology, Jinan University, Guangzhou, China.
authors.forename: Xiuying
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, Pennsylvania, USA zouc@upmc.edu mallampallirk@upmc.edu.
authors.forename: Chunbin
authors.initials: C
authors.lastname: Zou
authors.affiliation: Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, Pennsylvania, USA Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA Medical Specialty Service Line, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania, USA zouc@upmc.edu mallampallirk@upmc.edu.
authors.forename: Rama K
authors.initials: RK
authors.lastname: Mallampalli
mesh_terms: D000107:Acetylation; D002460:Cell Line; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism; D044783:F-Box Proteins / Q000378:metabolism*; D057809:HEK293 Cells; D006207:Half-Life; D006367:HeLa Cells; D006801:Humans; D054778:NM23 Nucleoside Diphosphate Kinases / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D044843:SKP Cullin F-Box Protein Ligases / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D054875:Ubiquitination / Q000502:physiology; D014945:Wound Healing / Q000502:physiology
chemical_list: D004268:DNA-Binding Proteins; D044783:F-Box Proteins; D054778:NM23 Nucleoside Diphosphate Kinases; D044843:SKP Cullin F-Box Protein Ligases; D044767:Ubiquitin-Protein Ligases