Radial spoke head protein 4 homolog A (RSPH4A)

Radial spoke head protein 4 homolog A (RSPH4A) is an evolutionarily conserved structural protein serving as a core component of the radial spoke head complex in motile cilia and flagella in humans and other eukaryotes[1][5][6]. It is essential for the assembly and structural stability of the radial spoke heads, serving as a scaffold that enables correct incorporation of additional spoke head proteins, such as RSPH1 and RSPH9, into the axoneme—the core structure of cilia and flagella[5][6]. Radial spokes play a vital role in regulating ciliary beat patterns by acting as a signal transduction scaffold between central and peripheral microtubules[1][5]. Mutations in RSPH4A compromise the architecture and function of motile cilia, leading to primary ciliary dyskinesia—a genetically heterogeneous disorder characterized by impaired mucociliary clearance, chronic respiratory infections, and male/female infertility[1][2][4][6][7]. RSPH4A mutations, specifically, are noted to produce especially severe ciliary ultrastructural defects resulting in pronounced clinical symptoms[4][7]. RSPH4A is not a druggable therapeutic target or classical receptor/enzyme/transporter, but acts as a crucial structural component for proper ciliary assembly and motility.

Other names

Radial spoke head-like protein 3RSHL3dJ412I7.1FLJ37974RSPH6BCILD11Radial spoke head protein 4 homolog ARadial spokehead-like 3