Abstract: The invention provides isolated nucleic acids molecules, designated 16816 or 16839 nucleic acid molecules, which encode novel phospholipase C family members. The invention also provides antisense nucleic acid molecules, recombinant expression vectors containing 16816 or 16839 nucleic acid molecules, host cells into which the expression vectors have been introduced, and nonhuman transgenic animals in which a 16816 or 16839 gene has been introduced or disrupted. The invention still further provides isolated 16816 or 16839 proteins, fusion proteins, antigenic peptides and anti-16816 or 16839 antibodies. Diagnostic methods utilizing compositions of the invention are also provided.