Basic and acidic fibroblast growth factors interact with the same cell surface receptors

Area of Science:

• Cell biology
• Molecular biology
• Biochemistry

Background:

• Basic and acidic fibroblast growth factors (FGF) exhibit similar activities on diverse cell types.
• This similarity suggests that both FGF types may interact with common cell surface receptors.
• Investigating these interactions is crucial for understanding FGF signaling pathways.

Purpose of the Study:

• To determine if basic and acidic FGF bind to the same cell surface receptors.
• To identify the specific receptor species involved in FGF binding.
• To elucidate the molecular basis for the differential potency of basic and acidic FGF.

Main Methods:

• Utilized a baby hamster kidney (BHK-21) cell line as a model system.
• Employed covalent cross-linking of 125I-labeled basic and acidic FGF to cell membrane components.
• Analyzed receptor binding using disuccinimidyl suberate and assessed competition assays with native FGF.

Main Results:

• Identified two receptor species with molecular masses of 145,000 and 125,000 daltons that bind FGF.
• Demonstrated that both basic and acidic FGF cross-link to both receptor species.
• Observed differential competition patterns, indicating distinct affinities of basic and acidic FGF for the identified receptors.

Conclusions:

• Basic and acidic FGF interact with common 145,000- and 125,000-dalton receptor species.
• Differential binding affinities of FGFs to these receptors explain their varying potencies.
• This finding provides insight into the molecular mechanisms of FGF-mediated cell growth and differentiation.