Practice question

LAG-2 is C. elegans Delta/Serrate/Lag2 family ligand for Notch receptors LIN-12 and GLP-1. Expressed in P2, anchor cell and primary VPC P6.p, LAG-2 extracellular DSL domain binds Notch extracellular EGF repeats triggering two proteolytic cleavages by ADAM and gamma-secretase, releasing Notch intracellular domain that complexes with LAG-1 to activate transcription. In AB lineage, LAG-2 from P2 activates GLP-1 to specify ABp fate; in vulva, LAG-2 from P6.p activates LIN-12 to specify secondary fates. Therefore general biochemical description is Notch ligand, essential for lateral and inductive Notch signaling in multiple cell fate decisions during early embryogenesis.