Fig. 3. WDFY4 is a BEACH domain-containing protein required for cross-presentation by cDC1s in vivo and in vitro.

The WDFY4 protein shares similarity with other members of the BEACH domain-containing protein family. The PH (green) and BEACH (blue) domains comprise nearly one-third of a protein, lying in the carboxy-terminal region along with other domains, namely, WD40 and FYVE repeats (brown). The first approximately 2000 amino acids lack defined domains, although ongoing research suggests that this region contains at least one larger armadillo domain. The precise mechanism by which this protein plays a required role in cross-presentation is unknown despite high profile speculations.