A new side to ubiquitin.
Mono-ubiquitination is a common mechanism of protein regulation, and more than ten ubiquitin-interacting domains that recognize the hydrophobic region centered on Ile44 of ubiquitin have been characterized. Two recent reports describe the crystal structure of the Rab5 guanine-nucleotide-exchange factor Rabex-5 and show that it contains two novel ubiquitin-binding domains. One of these is an A20 zinc finger that binds to a polar interaction interface of ubiquitin centered on Asp58. The discovery of an alternative interaction face of ubiquitin opens new avenues for understanding how this small protein regulates protein function.
Raiborg
Camilla
C
Department of Biochemistry, the Norwegian Radium Hospital and the University of Oslo, Montebello, N-0310 Oslo, Norway.
Slagsvold
Thomas
T
Stenmark
Harald
H
D000818:Animals; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008954:Models, Biological; D008958:Models, Molecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D025801:Ubiquitin / Q000737:chemistry / Q000378:metabolism*
D020662:Guanine Nucleotide Exchange Factors; C108382:RABGEF1 protein, human; D025801:Ubiquitin