Structural basis for the RNA binding properties of mouse IGF2BP3

Area of Science:

• Molecular Biology
• Structural Biology
• Gene Regulation

Background:

• Insulin-like Growth Factor 2 Binding Proteins (IGF2BPs) are crucial regulators of gene expression.
• These proteins possess complex RNA-binding properties due to multiple RNA-binding domains (RBDs).
• Understanding IGFBP-RNA interactions is key to deciphering their regulatory functions.

Purpose of the Study:

• To elucidate the structural mechanisms by which IGF2BP3 recognizes specific RNA targets.
• To provide detailed insights into the RNA-binding modes of IGF2BP3 domains.
• To compare RNA-binding properties across different IGF2BP3 domains.

Main Methods:

• Determination of crystal structures of mouse IGF2BP3 constructs bound to various RNA substrates.
• Biochemical assays to validate RNA-binding interactions.
• Comparative analysis of RNA-binding domain (RBD) characteristics.

Main Results:

• IGF2BP3's RRM12 domains recognize CA-rich elements (up to 5 nucleotides) primarily via RRM1.
• The KH12 domains exhibit an antiparallel RNA-binding mode, with KH1 binding five nucleotides and KH2 binding two.
• Evidence suggests IGF2BP3-KH12 domains can recognize the "zipcode" RNA element in β-actin mRNA.

Conclusions:

• Structural and biochemical data reveal specific RNA recognition strategies employed by IGF2BP3.
• The findings highlight distinct RNA-binding capabilities of IGF2BP3's RRM and KH domains.
• This study provides critical structural insights into IGF2BP3-mediated RNA target recognition.