Table 2

Cullin structures and cullin-RING E3 complex assembly

Protein

E3 components

Structures solved*

Key recognition fold on adaptor

Key determinants on cullin NTD


Adaptor

Substrate recognition

RING


CUL1

Skp1

F-box protein

ROC1/Rbx1

CUL1-Rbx1-Skp1-F boxSkp2 [6]; Skp1-Skp2 [60]

Skp1/BTB/POZ fold in Skp1 [6]

CUL1 H2 and H5 helices [6]

CUL2

EloC/EloB

VHL

ROC1/Rbx1

No CUL2 structure; VHL-EloC-EloB [60]

Skp1/BTB/POZ fold in EloC [6,61]

CUL2 H2 and H5 helices [14]

CUL3

BTB (adaptor-targeting)

BTB (adaptor-targeting)

ROC1/Rbx1

SPOP BTB-SBC [13]

BTB [13]; 3-box [13]

CUL3 H2 and H5 helices [62]

CUL4A

DDB1

DCAF

ROC1/Rbx1

DDB1-CUL4A-ROC1 [9]; DDB1-V protein [8]

BPB in DDB1 [9]

CUL4A H2 and H5 helices [9]; CUL4A amino-terminal extension [9]

CUL4B

DDB1

DCAF

ROC1/Rbx1

Not available

BPB in DDB1 (predicted)

CUL4B H2/H5 (predicted)

CUL5

EloC/EloB

SOCS protein

ROC2/Rbx2

CUL5CTD-Rbx1 [37]; SOCS2- EloC-EloB [63]; HIV Vif-EloC-EloB [16]

Skp1/BTB/POZ fold in EloC [6,61]

CUL5 H2 and H5 helices [64]; CUL5 loop 2 (amino acids 51 to 60) [16]; CUL5 loop 5 (amino acids 118 to 134) [16]

CUL7

Skp1

Fbw8

ROC1/Rbx1

CUL7 CPH-p53 TD [65]

Skp1/BTB/POZ fold in Skp1 (predicted)

Unknown

PARC

Unknown

Unknown

Unknown

Not available

Unknown

Unknown


*Crystal structures of CRL complexes were solved with recombinant human proteins.

Sarikas et al. Genome Biology 2011 12:220   doi:10.1186/gb-2011-12-4-220