1Q1U

Crystal structure of human FHF1b (FGF12b)

DOI: 10.2210/pdb1Q1U/pdb

Classification: HORMONE/GROWTH FACTOR
Organism(s): Homo sapiens
Expression System: Escherichia coli BL21
Mutation(s): Yes

Deposited: 2003-07-22 Released: 2003-08-05
Deposition Author(s): Olsen, S.K., Garbi, M., Zampieri, N., Eliseenkova, A.V., Ornitz, D.M., Goldfarb, M., Mohammadi, M.

Experimental Data Snapshot

Method: X-RAY DIFFRACTION
Resolution: 1.70 Å
R-Value Free: 0.240
R-Value Work: 0.223
R-Value Observed: 0.223

wwPDB Validation 3D Report Full Report

This is version 1.2 of the entry. See complete history.

Literature

Fibroblast growth factor (FGF) homologous factors share structural but not functional homology with FGFs

Olsen, S.K., Garbi, M., Zampieri, N., Eliseenkova, A.V., Ornitz, D.M., Goldfarb, M., Mohammadi, M.

(2003) J Biol Chem 278: 34226-34236

PubMed: 12815063 Search on PubMed
DOI: 10.1074/jbc.M303183200
Primary Citation of Related Structures:
1Q1U

PubMed Abstract:

Fibroblast growth factors (FGFs) interact with heparan sulfate glycosaminoglycans and the extracellular domains of FGF cell surface receptors (FGFRs) to trigger receptor activation and biological responses. FGF homologous factors (FHF1-FHF4; also known as FGF11-FGF14) are related to FGFs by substantial sequence homology, yet their only documented interactions are with an intracellular kinase scaffold protein, islet brain-2 (IB2) and with voltage-gated sodium channels. In this report, we show that recombinant FHFs can bind heparin with high affinity like classical FGFs yet fail to activate any of the seven principal FGFRs. Instead, we demonstrate that FHFs bind IB2 directly, furthering the contention that FHFs and FGFs elicit their biological effects by binding to different protein partners. To understand the molecular basis for this differential target binding specificity, we elucidated the crystal structure of FHF1b to 1.7-A resolution. The FHF1b core domain assumes a beta-trefoil fold consisting of 12 antiparallel beta strands (beta 1 through beta 12). The FHF1b beta-trefoil core is remarkably similar to that of classical FGFs and exhibits an FGF-characteristic heparin-binding surface as attested to by the number of bound sulfate ions. Using molecular modeling and structure-based mutational analysis, we identified two surface residues, Arg52 in the beta 4-beta 5 loop and Val95 in the beta 9 strand of FHF1b that are required for the interaction of FHF1b with IB2. These two residues are unique to FHFs, and mutations of the corresponding residues of FGF1 to Arg and Val diminish the capacity of FGF1 to activate FGFRs, suggesting that these two FHF residues contribute to the inability of FHFs to activate FGFRs. Hence, FHFs and FGFs bear striking structural similarity but have diverged to direct related surfaces toward interaction with distinct protein targets.

Organizational Affiliation:

Department of Pharmacology, New York University School of Medicine, New York, New York 10016, USA.

Macromolecules

Find similar proteins by:

(by identity cutoff) | Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
fibroblast growth factor homologous factor 1	A	144	Homo sapiens	Mutation(s): 1 Gene Names: FGF12, FGF12B, FHF1
Find proteins for P61328 (Homo sapiens) Explore P61328 Go to UniProtKB: P61328
NIH Common Fund Data Resources
PHAROS: P61328 GTEx: ENSG00000114279
Protein Feature View Expand
Reference Sequence

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram	3D Interactions
SO4 Query on SO4 Download Ideal Coordinates CCD File SDF format, chain B [A] SDF format, chain C [A] SDF format, chain D [A] SDF format, chain E [A] MOL2 format, chain B [A] MOL2 format, chain C [A] MOL2 format, chain D [A] MOL2 format, chain E [A]	A	SULFATE ION O₄ S QAOWNCQODCNURD-UHFFFAOYSA-L		Ligand Interaction