About B9 Protein:
The B9 protein is the product of the B9D1 (B9 domain containing 1) gene. It is also called MKRS-1, EPPB9 and “endothelial precursor protein B9.”
The B9 protein is involved in ciliogenesis - a process that involves the building of cell antennae that enable cells and bacteria to interact with their environments and move through fluids.
B9 Protein Function
Changes in the chemical structure of the B9D1 (B9 domain-containing 1) gene is present in families with Meckel Syndrome - a lethal developmental condition that features posterior fossa abnormalities, (particularly of the occipital encephalocele), development defects in the liver, and cystic enlargement of both kidneys. Dysfunction of the B9D1 protein-coding gene is also associated with Joubert Syndrome 27, a disease characterised by developmental delays, hypotonia, cerebellar and brainstem malformation.
The B9D1-coding gene is responsible for the biogenesis of cellular organelles and maintenance. It also appears to play a role in PLK1 activity and G2/M transitions. These transitions form critical parts of the pathway network that leads from polo-like kinase-mediated events to the recruitment of mitotic centrosome proteins and complexions, anchoring of the basal body to the plasma membrane, AURKA activation by TPX2 and recruitment of NuMA to mitotic centrosomes.
B9 Protein Interactions
The purpose of the B9D1 gene appears to be to prevent the diffusion of transmembrane proteins between the plasma membranes and cilia. It is a critical component of the tectonic-like complex - an important player in non-motile ciliopathies.
Dysfunction of the primary cilium in mammalian cells results in complex and heterogeneous pathologies. B9D1 and B9 protein malformation may combine with other gene mutations to cause dysfunction.