Neurons L2-4 and L6, also called giant dorsal LUQ (Left Upper Quadrant) neurons of the abdominal ganglion. Also expressed in smaller neurons in the CNS and in peripheral organs such as the kidney. The prohormone is proteolytically cleaved in 2 steps, yielding first 2 products: luqin and PRMP. In the second step, PRMP is cleaved to yield luqin-B and luqin-C. Was previously thought to be expressed in L5.