Purification and Structural Analysis of LEM-Domain Proteins

Area of Science:

• Nuclear biology
• Protein structure and function
• Molecular genetics

Background:

• LAP2-emerin-MAN1 (LEM)-domain proteins are a family of modular proteins.
• Most LEM-domain proteins are found at the inner nuclear membrane, but some reside in the endoplasmic reticulum or nuclear interior.

Purpose of the Study:

• To analyze the architecture of LEM-domain proteins.
• To characterize the structure and function of their globular domains and interactions with other molecules like DNA and chromatin.

Main Methods:

• Prediction of globular domain limits.
• Determination of 3D structures of globular domains.
• Calculation of 3D structures for specific domains bound to targets.
• Characterization of other globular domains (e.g., LAP2α C-terminal dimerization domain, MAN1 C-terminal WH and UHM domains).

Main Results:

• The LEM domain exhibits an α-helical fold, conserved across species.
• LEM domains bind to barrier-to-autointegration factor (BAF), which links DNA and chromatin to the nuclear envelope.
• LAP2 isoforms possess an N-terminal LEM-like domain that binds DNA.
• Intrinsically disordered regions in LEM-domain proteins are involved in interactions and are regulated by posttranslational modifications.

Conclusions:

• LEM-domain proteins have diverse structures and functions, with the conserved LEM domain playing a critical role in binding BAF and interacting with DNA.
• The characterized domains and intrinsically disordered regions highlight the complexity of LEM-domain proteins in nuclear organization and regulation.