Cytoplasmic dynein-2 is the motor for retrograde intraflagellar transport (IFT), 
and mutations in dynein-2 are known to cause skeletal ciliopathies. Here, we 
define for the first time the composition of the human cytoplasmic dynein-2 
complex. We show that the proteins encoded by the ciliopathy genes WDR34 and 
WDR60 are bona fide dynein-2 intermediate chains and are both required for 
dynein-2 function. In addition, we identify TCTEX1D2 as a unique dynein-2 light 
chain that is itself required for cilia function. We define several subunits 
common to both dynein-1 and dynein-2, including TCTEX-1 (also known as DYNLT1) 
and TCTEX-3 (also known as DYNLT3), roadblock-1 (also known as DYNLRB1) and 
roadblock-2 (also known as DYNLRB2), and LC8-1 and LC8-2 light chains (DYNLL1 
and DYNLL2, respectively). We also find that NudCD3 associates with dynein-2 as 
it does with dynein-1. By contrast, the common dynein-1 regulators dynactin, 
LIS1 (also known as PAFAH1B1) and BICD2 are not found in association with 
dynein-2. These data explain why mutations in either WDR34 or WDR60 cause 
disease, as well as identifying TCTEX1D2 as a candidate ciliopathy gene.