Changes in the ratio of free NEDD8 to ubiquitin triggers NEDDylation by ubiquitin enzymes

TY - JOUR

T1 - Changes in the ratio of free NEDD8 to ubiquitin triggers NEDDylation by ubiquitin enzymes

A1 - Hjerpe,Roland

A1 - Thomas,Yann

A1 - Chen,Jesse

A1 - Zemla,Aleksandra

A1 - Curran,Siobhan

A1 - Shpiro,Natalia

A1 - Dick,Lawrence R.

A1 - Kurz,Thimo

AU - Hjerpe,Roland

AU - Thomas,Yann

AU - Chen,Jesse

AU - Zemla,Aleksandra

AU - Curran,Siobhan

AU - Shpiro,Natalia

AU - Dick,Lawrence R.

AU - Kurz,Thimo

PY - 2012/2/1

Y1 - 2012/2/1

N2 - <p>Ubiquitin and UBL (ubiquitin-like) modifiers are small proteins that covalently modify other proteins to alter their properties or behaviours. Ubiquitin modification (ubiquitylation) targets many substrates, often leading to their proteasomal degradation. NEDD8 (neural-precursor-cell-expressed developmentally down-regulated 8) is the UBL most closely related to ubiquitin, and its best-studied role is the activation of CRLs (cullin-RING ubiquitin ligases) by its conjugation to a conserved C-terminal lysine residue on cullin proteins. The attachment of UBLs requires three UBL-specific enzymes, termed E1, E2 and E3, which are usually well insulated from parallel UBL pathways. In the present study, we report a new mode of NEDD8 conjugation (NEDDylation) whereby the UBL NEDD8 is linked to proteins by ubiquitin enzymes in vivo. We found that this atypical NEDDylation is independent of classical NEDD8 enzymes, conserved from yeast to mammals, and triggered by an increase in the NEDD8 to ubiquitin ratio. In cells, NEDD8 overexpression leads to this type of NEDDylation by increasing the concentration of NEDD8, whereas proteasome inhibition has the same effect by depleting free ubiquitin. We show that bortezomib, a proteasome inhibitor used in cancer therapy, triggers atypical NEDDylation in tissue culture, which suggests that a similar process may occur in patients receiving this treatment.</p>

AB - <p>Ubiquitin and UBL (ubiquitin-like) modifiers are small proteins that covalently modify other proteins to alter their properties or behaviours. Ubiquitin modification (ubiquitylation) targets many substrates, often leading to their proteasomal degradation. NEDD8 (neural-precursor-cell-expressed developmentally down-regulated 8) is the UBL most closely related to ubiquitin, and its best-studied role is the activation of CRLs (cullin-RING ubiquitin ligases) by its conjugation to a conserved C-terminal lysine residue on cullin proteins. The attachment of UBLs requires three UBL-specific enzymes, termed E1, E2 and E3, which are usually well insulated from parallel UBL pathways. In the present study, we report a new mode of NEDD8 conjugation (NEDDylation) whereby the UBL NEDD8 is linked to proteins by ubiquitin enzymes in vivo. We found that this atypical NEDDylation is independent of classical NEDD8 enzymes, conserved from yeast to mammals, and triggered by an increase in the NEDD8 to ubiquitin ratio. In cells, NEDD8 overexpression leads to this type of NEDDylation by increasing the concentration of NEDD8, whereas proteasome inhibition has the same effect by depleting free ubiquitin. We show that bortezomib, a proteasome inhibitor used in cancer therapy, triggers atypical NEDDylation in tissue culture, which suggests that a similar process may occur in patients receiving this treatment.</p>

KW - bortezomib

KW - MG132

KW - MLN4924

KW - neural-precursor-cell-expressed developmentally down-regulated 8 (NEDD8)-activating enzyme (NAE)

KW - proteasome

KW - ubiquitin-activating enzyme

KW - TRANSCRIPTIONAL ACTIVITY

KW - CULLIN NEDDYLATION

KW - E3 LIGASE

KW - PROTEIN

KW - PATHWAY

KW - E1

KW - CONJUGATION

KW - PROTEASOME

KW - INHIBITOR

KW - CANCER

U2 - 10.1042/BJ20111671

DO - 10.1042/BJ20111671

M1 - Article

JO - Biochemical Journal

JF - Biochemical Journal

SN - 0264-6021

VL - 441

SP - 927

EP - 936

ER -