Galectin-3 interacts with components of the nuclear ribonucleoprotein complex

Area of Science:

• Molecular Biology
• Cell Biology
• Cancer Research

Background:

• Galectin-3, a β-galactoside-binding protein, localizes to various cellular compartments, including the nucleus.
• Changes in galectin-3 expression and distribution correlate with cell differentiation and cancer development.
• The specific nuclear functions of galectin-3 in tumorigenesis remain largely unknown.

Purpose of the Study:

• To identify nuclear galectin-3 interacting partners.
• To investigate the role of galectin-3 in mRNA export and processing.
• To elucidate the contribution of nuclear galectin-3 to cancer development.

Main Methods:

• Affinity chromatography and co-immunoprecipitation to identify binding partners.
• Immunofluorescence and proximity ligation assays for spatial proximity analysis.
• Fluorescence in situ hybridization and RNA-sequencing to assess mRNA export and processing.

Main Results:

• hnRNPA2B1 was identified as a novel nuclear galectin-3 binding protein, with binding dependent on lactose.
• Individual depletion of galectin-3 did not affect mRNA distribution, but combined depletion with galectin-1 did.
• Silencing galectin-3 alone altered splicing patterns for several genes.

Conclusions:

• Galectin-3 and hnRNPA2B1 interact within the early splicing machinery.
• Galectin-3 and galectin-1 exhibit redundant functions in mRNA transport and splicing.
• The hnRNPA2B1/galectin-3 interaction specifically influences the processing of transcripts encoding the nuclear oncoprotein SET.