WD40 repeat

WD40 Repeat

Structure of a WD40 repeat protein showing the 7-bladed beta-propeller.

The WD40 repeat is a short structural motif of approximately 40 amino acids, often terminating in a tryptophan-aspartic acid (WD) dipeptide. These repeats are found in a wide variety of proteins and are involved in a diverse range of cellular processes, including signal transduction, RNA processing, and cytoskeletal assembly.

Structure

WD40 repeats typically form a beta-propeller structure, which consists of 4 to 8 repeating units that create a circular, symmetrical shape. Each repeat forms a beta-sheet, and together they create a stable, propeller-like structure. This configuration allows for multiple protein-protein interactions, making WD40 repeat proteins versatile scaffolds in cellular processes.

Function

WD40 repeat proteins are involved in a variety of cellular functions. They often serve as platforms for the assembly of protein complexes, facilitating interactions between different proteins. This makes them crucial in processes such as signal transduction, where they can act as adaptors or scaffolds that bring together various signaling molecules.

In addition to their role in signaling, WD40 repeat proteins are also involved in RNA processing, where they can influence the splicing and modification of RNA molecules. They are also important in the regulation of the cytoskeleton, affecting cell shape and motility.

Examples

Some well-known proteins that contain WD40 repeats include:

• Beta-transducin repeat containing protein (_-TrCP), which is involved in the ubiquitination and subsequent degradation of target proteins.
• G-protein beta subunit, which is part of the heterotrimeric G-protein complex involved in signal transduction.
• E3 ubiquitin-protein ligase CUL4A, which is part of the ubiquitin-proteasome system that regulates protein degradation.

Related pages

• Protein structure
• Signal transduction
• RNA processing
• Cytoskeleton