Pull down assay for GTP-bound form of Sar1a reveals its activation during morphological differentiation.

The intracellular molecular transport system is a basic and general cellular mechanism that is regulated by an array of signaling molecules. Sar1 small GTPases are molecules that play a key role in controlling vehicle transport between the endoplasmic reticulum (ER) and Golgi bodies. Like other small GTPases, the activities of Sar1a depend on their guanine-nucleotide-binding states, which are regulated by guanine-nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs).

Treacher Collins syndrome 3 (TCS3)-associated POLR1C mutants are localized in the lysosome and inhibits chondrogenic differentiation.

Treacher Collins syndrome (TCS) is a craniofacial developmental disorder whose key feature is a combination of symptoms. For example, a patient could have bilateral downward slanting of the palpebral fissures, colobomas of the lower eyelids, hypoplasia of the facial bones, cleft palate, malformation of the external ears, and atresia of the external auditory canals. TCS3 is caused by mutations of the polr1c gene, which encodes RNA polymerase I and III subunit C (POLR1C).

Dystonia-4 (DYT4)-associated TUBB4A mutants exhibit disorganized microtubule networks and inhibit neuronal process growth.

Dystonia-1 (DYT1) is an autosomal dominant early-onset torsion form of dystonia, a neurological disease affecting movement. DYT1 is the prototypic hereditary dystonia and is caused by the mutation of the tor1a gene. The gene product has chaperone functions important for the control of protein folding and stability.