Acts as one of several non-catalytic accessory components of the cytoplasmic dynein 2 complex (dynein-2 complex), a motor protein complex that drives the movement of cargos along microtubules within cilia and flagella in concert with the intraflagellar transport (IFT) system (PubMed:23910462, PubMed:25205765, PubMed:29742051, PubMed:31451806). DYNC2I1 plays a major role in retrograde ciliary protein trafficking in cilia and flagella (PubMed:29742051, PubMed:30320547, PubMed:30649997). Also requires to maintain a functional transition zone (PubMed:30320547). {ECO:0000269|PubMed:23910462, ECO:0000269|PubMed:25205765, ECO:0000269|PubMed:29742051, ECO:0000269|PubMed:30320547, ECO:0000269|PubMed:30649997, ECO:0000269|PubMed:31451806}. This is the function of DYNC2I1 (dynein 2 intermediate chain 1, ENSG00000126870).