Regulates macropinocytosis in pericardial cells. Expressed in all postembryonic pericardial cells, but not in cardioblasts. Also expressed in Garland cells in third instar larvae (at protein level). Not expressed during embryonic development and first instar larvae. Expression detected from second instar larval stage into adulthood (at protein level). Has been proposed to contain 7 WD repeats. This prediction could not be reproduced. RNAi-mediated knockdown of the protein in the hematopoietic system and pericardial cells causes a decrease in macropinocytic uptake by pericardial cells. Belongs to the BCAS3 family.