Which of the following statements about Ig Fc receptors is NOT true?
A)Some Fc receptors or Fc receptor-associated signaling chains contain ITAMs in their cytoplasmic tails.
B)Some Fc receptors are linked to signal transduction pathways that cause granule exocytosis.
C)There are Fc receptors specific for all common Ig isotypes.
D)Some Fc receptors with ITIMs in their cytoplasmic tails transduce inhibitory signals.
E)Fc receptor signaling may enhance generation of reactive oxygen intermediates in phagocytes.

Question

Quizplus · Accepted Answer

There are no IgM-binding Fc receptors.Most Fc receptors transduce activating signals on binding Ig.The signals may be linked to many different functional responses.In phagocytes,these include generation of reactive oxygen intermediates that are toxic to ingested microbes.In mast cells,eosinophils,and natural killer cells,Fc receptor signaling stimulates granule exocytosis.Signaling depends on recruitment of molecules to ITAM motifs that are in the cytoplasmic tails of the Ig binding polypeptide,or non-Ig-binding signaling chains that are associated with the Fc receptor.The FcF1F1F1S1F1F1F10RIIB receptor on B cells transduces inhibitory signals via a tyrosine phosphatase-binding ITIM domain in its cytoplasmic tail.

Which of the Following Statements About Ig Fc Receptors Is