SR protein

Protein SFRS9 PDB 1wg4

File:SR proteins translocation into and out of the nucleus.png

SR proteins translocation into and out of the nucleus

File:SR proteins competing with hnRNPs.png

SR proteins competing with hnRNPs

SR proteins are a family of RNA-binding proteins that play a crucial role in RNA splicing, a process essential for the maturation of messenger RNA (mRNA) in eukaryotic cells. These proteins are characterized by the presence of one or two RNA recognition motifs (RRMs) at their N-terminus and a C-terminal domain rich in serine and arginine residues, known as the RS domain.

Structure

SR proteins typically contain:

• One or two RNA recognition motifs (RRMs) at the N-terminus.
• A C-terminal domain rich in serine and arginine residues, known as the RS domain.

Function

SR proteins are involved in multiple steps of the RNA splicing process, including:

• Spliceosome assembly
• Splice site selection
• Regulation of alternative splicing

They also play roles in other aspects of RNA metabolism, such as mRNA export, nonsense-mediated decay, and translation.

Mechanism

SR proteins function by binding to exonic splicing enhancers (ESEs) within the pre-mRNA. This binding facilitates the recruitment of the spliceosome components to the correct splice sites, ensuring accurate and efficient splicing.

Regulation

The activity of SR proteins is regulated by phosphorylation of their RS domain. Kinases such as SRPK1 and CLK1 phosphorylate SR proteins, modulating their interaction with other splicing factors and RNA.

Clinical Significance

Mutations or dysregulation of SR proteins have been implicated in various diseases, including:

• Cancer
• Spinal muscular atrophy
• Myotonic dystrophy

List of SR Proteins

Some well-known SR proteins include:

• SRSF1
• SRSF2
• SRSF3
• SRSF4
• SRSF5

Related Pages

• RNA splicing
• Spliceosome
• RNA-binding protein
• Exonic splicing enhancer
• Phosphorylation