In a yeast two-hybrid screen using the Drosophila Axin protein as a bait, we have identified a Drosophila homolog of CAP, a component of the glucose transport regulatory complex. Through alternative splicing, the DCAP gene generates a set of five different proteins with unique N-terminal sequences and a common C-terminal SH3 domain. DCAP is predominantly expressed in the midgut and fat bodies of late-stage embryos, suggesting a role in insulin-mediated glucose transport in these organs.