Plays a role in pre-mRNA splicing by regulating the release and transfer of U4/U6.U5 tri-small nuclear ribonucleoprotein (tri-snRNP) complexes from their assembly site in Cajal bodies to nuclear speckles, thereby contributing to the assembly of the pre-catalytic spliceosome on target pre-mRNAs (By similarity). May also participate in recycling of snRNPs back to Cajal bodies during splicing (By similarity). Plays a role in regulating MAGI2-mediated endocytosis (By similarity). Anchoring/scaffolding protein that is a part of the functional network formed by USH1C, USH1G, CDH23 and MYO7A that mediates mechanotransduction in cochlear hair cells. Required for normal development and maintenance of cochlear hair cell bundles. Required for normal hearing. Part of a complex composed of USH1C, USH1G and MYO7A (By similarity). Interacts with USH1C (via the first PDZ domain) (PubMed:12588794). Interacts with PDZD7 (By similarity). Interacts with CDH23 and PCDH15; these interactions may recruit USH1G to the plasma membrane (PubMed:21436032). Interacts with intraflagellar transport proteins IFT20, IFT52 AND IFT57 (By similarity). Interacts with splicing factors SF3B1, PRPF6, PRPF31 and SON (By similarity). Interacts with the U4/U6.U5 tri-small nuclear ribonucleoprotein (tri-snRNP) complex in the presence of pre-mRNAs (By similarity). Interacts (via SAM domain) with MAGI2 (via PDZ 6 domain); the interaction is triggered by phosphorylation of USH1G by CK2 and negatively regulates MAGI2-mediated endocytosis (PubMed:24608321). Detected at the tip of cochlear hair cell stereocilia. Recruited to the cell membrane via interaction with CDH23 or PCDH15 (PubMed:21436032). In photoreceptor cilia, detected predominantly at the cilium base (PubMed:31637240). Expressed in the pericentriolar region of the centrosome (PubMed:24608321). Detected in stereocilia from cochlear hair cells (at protein level). Detected in retinal photoreceptor cell cilia (at protein level) (PubMed:31637240). Highly expressed in the cochlea, testis, cerebellum and eye, and low levels in brain, thymus and spleen. Significant signals detected in the neurosensory epithelium of inner ear cochlea and saccule, especially in inner and outer hair cells. Low-level expression detected in 17.5 dpc embryos but not in embryos earlier than 15.5 dpc. Defects in Ush1g are the cause of the Jackson shaker phenotypes (js). Jackson shaker mice carry recessive mutations predicted to inactivate Ush1g by frameshift resulting in a truncated protein lacking the C-terminal SAM domain. The js phenotype is characterized by deafness, abnormal behavior (circling and/or head-tossing) and degeneration of inner ear neuroepithelia. Defects in the formation of protein complex including Ush1g may disrupt stereocilia bundle in js mice. Mice are deaf, due to defects in hair cell bundles in the cochlea (PubMed:21436032). They develop circling behavior, probably due to balance problems (PubMed:21436032). Reduced expression of Ift20, Ift52 and Ift57 in the ciliary region of photoreceptor cells (PubMed:31637240).