背景资料：Members of the 'frizzled' gene family encode 7-transmembrane domain proteins that are receptors for Wnt signaling proteins. The FZD1 protein contains a signal peptide, a cysteine-rich domain in the N-terminal extracellular region, 7 transmembrane domains, and a C-terminal PDZ domain-binding motif. The FZD1 transcript is expressed in various tissues. May be involved in transduction and intercellular transmission of polarity information during tissue morphogenesis and/or in differentiated tissues. Activated by Wnt3A, Wnt3, Wnt1 and to a lesser extent Wnt2, but not by Wnt4, Wnt5A, Wnt5B, Wnt6, Wnt7A or Wnt7B.