The PSGL-1 cytoplasmic tail interacts with moesin.

(A) GST fusion proteins were generated, which incorporated the PSGL-1 cytoplasmic domain (lane 3), or GST only (negative control, lane 2), and were incubated with HL60 WCLs. The blot was probed with a rabbit pAb to moesin, which also recognizes ezrin. GST fusion proteins expressing the cytoplasmic tail of PSGL-1 (lane 3) affinity captured moesin, but not ezrin. (B) Coimmunoprecipitations of WCLs from PSGL-1 or PSGL-1Δcyto transfectants were performed with the anti-PSGL-1 mAb KPL1 coupled to Affigel followed by Western blotting with an antimoesin mAb (left panel) or KPL-1 (right panel). Interactions with moesin were detected in either untreated WCLs (left panel, lane 1) or immunoprecipitates from PSGL-1 transfectants (left panel, lane 2), but not PSGL-1Δcyto transfectants (left panel, lane 3). Probing of either untreated WCLs (right panel, lane 1) or immunoprecipitates from PSGL-1 (right panel, lane 2) or PSGL-1Δcyto (right panel, lane 3) with KPL1 revealed either full-length (lane 1 and lane 2) or truncated (lane 3) PSGL-1.