Nuclear targeting of cAMP response element binding protein 2 (CREB2)

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• CREB2 is a transcription factor with DNA-binding and dimerization domains.
• Previous studies indicated CREB2 localizes to the nucleus.

Purpose of the Study:

• To identify the specific signals responsible for nuclear targeting of CREB2.
• To elucidate the role of CREB2's domains in its subcellular localization.

Main Methods:

• Indirect immunofluorescence labeling of COS cells expressing CREB2 fusion proteins.
• Deletion mutagenesis and single point mutations within the CREB2 basic region.
• Assay of cellular location using antibodies against glutathione S-transferase.

Main Results:

• The nuclear targeting signal for CREB2 resides in its C-terminal region.
• The basic region (amino acids 280-300) is sufficient for nuclear localization.
• The KKLKK sequence (amino acids 280-284) within the basic region is critical for nuclear targeting.

Conclusions:

• The basic region of CREB2 is essential for both DNA binding and nuclear localization.
• Efficient nuclear sorting of CREB2 requires sequences beyond the basic region.
• CREB2's nuclear import mechanism involves specific amino acid sequences within its DNA-binding domain.