0000000000173669
AUTHOR
E. Van Wijk
PDZD7 connects the Usher protein complex to the intraflagellar transport machinery
Several Usher syndrome (USH)-associated proteins are known to localize to the connecting cilium of photoreceptor cells. The unconventional myosin MYO7A (USH1B) was long accepted as the transport molecule responsible for the ciliary localization of USH proteins. However, based on the typical location of several of the USH proteins along the ciliary axoneme, the involvement of the main ciliary trafficking machinery, intraflagellar transport (IFT), seems apparent. The USH-associated scaffold protein PDZD7 is known to interact with SANS, Usherin, GPR98 and Whirlin, all of which can be found in the connecting cilium. Here, we report that PDZD7 provides the physical link of the USH-protein networ…
The Usher syndrome 1G protein SANS participates in the transport of ciliary cargo in photoreceptor cells
Human Usher syndrome (USH) is the most common form of combined deaf-blindness, characterized by profound congenital deafness, constant vestibular dysfunction and pre-pubertal onset of retinitis pigmentosa. The USH1G protein SANS (scaffold protein containing ankyrin repeats and SAM domain) is associated with microtubules and mediates a transport related periciliary protein network in photoreceptor cells. Here we aim to enlighten the involvement of SANS in ciliary transport of photoreceptor cells by identifying proteins associated with SANS in transport complexes. In Y2H screen of retinal cDNA library we identified the direct binding of SANS to dynactin-1 (p150Glued), a subunit of the dynacti…
Direct binding of Magi2 to the USH1G protein SANS links the periciliary USH protein network to endocytosis
The human Usher syndrome (USH) is the most common form of combined deaf-blindness. The encoded molecules are integrated into protein networks by scaffolds including the USH1G protein SANS (scaffold protein containing ankyrin repeats and SAM domain). Previous studies indicated SANS´ participation in vesicle transport and cargo handover at the periciliary region of photoreceptor cells. To decipher the precise cellular role of SANS, we searched for interacting partners. Therefore we adopted a yeast-2-hybrid screen of a retinal cDNA library using SANS´ C-terminus as bait. Amongst others we identified the MAGUK protein Magi2 (membrane-associated guanylate kinase inverted-2) as putative binding p…
Identification of novel interaction partners for Vlgr1b/GPR98 - a key component of the periciliary Usher syndrome protein network in photoreceptor cells
The human Usher syndrome (USH) is the most common form of combined hereditary deaf-blindness. Three clinical subtypes (USH1-3) are differentiated based on severity, age of onset and progression of the symptoms. Mutations in the GPR98 gene encoding the USH2C protein Vlgr1b or GPR98 cause USH2, the most common form of USH. The G-protein coupled receptor Vlgr1b was previously identified as a component of the periciliary USH protein network, crucial for ciliary cargo transport in photoreceptors. Nonetheless, the exact role of Vlgr1b in this and other cellular processes remains to be elucidated. To learn more about its involvement in cellular functions we searched for novel interaction partners …