FGF21 N- and C-termini play different roles in receptor interaction and activation.
Fibroblast growth factor-21 (FGF21) signaling requires the presence of beta-Klotho, a co-receptor with a very short cytoplasmic domain. Here we show that FGF21 binds directly to beta-Klotho through its C-terminus. Serial C-terminal truncations of FGF21 weakened or even abrogated its interaction with beta-Klotho in a Biacore assay, and led to gradual loss of potency in a luciferase reporter assay but with little effect on maximal response. In contrast, serial N-terminal truncations of FGF21 had no impact on beta-Klotho binding. Interestingly, several of them exhibited characteristics of partial agonists with minimal effects on potency. These data demonstrate that the C-terminus of FGF21 is critical for binding to beta-Klotho and the N-terminus is critical for fibroblast growth factor receptor (FGFR) activation.
Yie
Junming
J
Department of Metabolic Disorders, Amgen Inc., Thousand Oaks, CA 91320, USA. jyie@amgen.com
Hecht
Randy
R
Patel
Jennifer
J
Stevens
Jennitte
J
Wang
Wei
W
Hawkins
Nessa
N
Steavenson
Shirley
S
Smith
Steve
S
Winters
Dwight
D
Fisher
Seth
S
Cai
Ling
L
Belouski
Ed
E
Chen
Ching
C
Michaels
Mark L
ML
Li
Yue-Sheng
YS
Lindberg
Richard
R
Wang
Minghan
M
Véniant
Murielle
M
Xu
Jing
J
D000595:Amino Acid Sequence; D002460:Cell Line; D005346:Fibroblast Growth Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D006801:Humans; D000090265:Klotho Proteins; D008156:Luciferases / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D051496:Receptor, Fibroblast Growth Factor, Type 1 / Q000378:metabolism*
C538995:KLB protein, human; D008565:Membrane Proteins; C414620:fibroblast growth factor 21; D005346:Fibroblast Growth Factors; D008156:Luciferases; C496348:FGFR1 protein, human; D051496:Receptor, Fibroblast Growth Factor, Type 1; D000090265:Klotho Proteins