Loop 7 of E2 enzymes: an ancestral conserved functional motif involved in the E2-mediated steps of the ubiquitination cascade
Research output: Contribution to journal › Journal article › Research › peer-review
Standard
Loop 7 of E2 enzymes : an ancestral conserved functional motif involved in the E2-mediated steps of the ubiquitination cascade. / Papaleo, Elena; Casiraghi, Nicola; Arrigoni, Alberto; Vanoni, Marco; Coccetti, Paola; De Gioia, Luca.
In: PLOS ONE, Vol. 7, No. 7, e40786, 2012.Research output: Contribution to journal › Journal article › Research › peer-review
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - JOUR
T1 - Loop 7 of E2 enzymes
T2 - an ancestral conserved functional motif involved in the E2-mediated steps of the ubiquitination cascade
AU - Papaleo, Elena
AU - Casiraghi, Nicola
AU - Arrigoni, Alberto
AU - Vanoni, Marco
AU - Coccetti, Paola
AU - De Gioia, Luca
PY - 2012
Y1 - 2012
N2 - The ubiquitin (Ub) system controls almost every aspect of eukaryotic cell biology. Protein ubiquitination depends on the sequential action of three classes of enzymes (E1, E2 and E3). E2 Ub-conjugating enzymes have a central role in the ubiquitination pathway, interacting with both E1 and E3, and influencing the ultimate fate of the substrates. Several E2s are characterized by an extended acidic insertion in loop 7 (L7), which if mutated is known to impair the proper E2-related functions. In the present contribution, we show that acidic loop is a conserved ancestral motif in E2s, relying on the presence of alternate hydrophobic and acidic residues. Moreover, the dynamic properties of a subset of family 3 E2s, as well as their binary and ternary complexes with Ub and the cognate E3, have been investigated. Here we provide a model of L7 role in the different steps of the ubiquitination cascade of family 3 E2s. The L7 hydrophobic residues turned out to be the main determinant for the stabilization of the E2 inactive conformations by a tight network of interactions in the catalytic cleft. Moreover, phosphorylation is known from previous studies to promote E2 competent conformations for Ub charging, inducing electrostatic repulsion and acting on the L7 acidic residues. Here we show that these active conformations are stabilized by a network of hydrophobic interactions between L7 and L4, the latter being a conserved interface for E3-recruitment in several E2s. In the successive steps, L7 conserved acidic residues also provide an interaction interface for both Ub and the Rbx1 RING subdomain of the cognate E3. Our data therefore suggest a crucial role for L7 of family 3 E2s in all the E2-mediated steps of the ubiquitination cascade. Its different functions are exploited thank to its conserved hydrophobic and acidic residues in a finely orchestrate mechanism.
AB - The ubiquitin (Ub) system controls almost every aspect of eukaryotic cell biology. Protein ubiquitination depends on the sequential action of three classes of enzymes (E1, E2 and E3). E2 Ub-conjugating enzymes have a central role in the ubiquitination pathway, interacting with both E1 and E3, and influencing the ultimate fate of the substrates. Several E2s are characterized by an extended acidic insertion in loop 7 (L7), which if mutated is known to impair the proper E2-related functions. In the present contribution, we show that acidic loop is a conserved ancestral motif in E2s, relying on the presence of alternate hydrophobic and acidic residues. Moreover, the dynamic properties of a subset of family 3 E2s, as well as their binary and ternary complexes with Ub and the cognate E3, have been investigated. Here we provide a model of L7 role in the different steps of the ubiquitination cascade of family 3 E2s. The L7 hydrophobic residues turned out to be the main determinant for the stabilization of the E2 inactive conformations by a tight network of interactions in the catalytic cleft. Moreover, phosphorylation is known from previous studies to promote E2 competent conformations for Ub charging, inducing electrostatic repulsion and acting on the L7 acidic residues. Here we show that these active conformations are stabilized by a network of hydrophobic interactions between L7 and L4, the latter being a conserved interface for E3-recruitment in several E2s. In the successive steps, L7 conserved acidic residues also provide an interaction interface for both Ub and the Rbx1 RING subdomain of the cognate E3. Our data therefore suggest a crucial role for L7 of family 3 E2s in all the E2-mediated steps of the ubiquitination cascade. Its different functions are exploited thank to its conserved hydrophobic and acidic residues in a finely orchestrate mechanism.
KW - Amino Acid Motifs
KW - Amino Acid Sequence
KW - Amino Acids
KW - Animals
KW - Cluster Analysis
KW - Conserved Sequence
KW - Humans
KW - Hydrophobic and Hydrophilic Interactions
KW - Molecular Dynamics Simulation
KW - Molecular Sequence Data
KW - Motion
KW - Phosphorylation
KW - Phylogeny
KW - Protein Binding
KW - Protein Stability
KW - Protein Structure, Secondary
KW - Protein Structure, Tertiary
KW - Static Electricity
KW - Ubiquitin
KW - Ubiquitin-Conjugating Enzymes
KW - Ubiquitination
U2 - 10.1371/journal.pone.0040786
DO - 10.1371/journal.pone.0040786
M3 - Journal article
C2 - 22815819
VL - 7
JO - PLoS ONE
JF - PLoS ONE
SN - 1932-6203
IS - 7
M1 - e40786
ER -
ID: 108138433