Frequenin: Proteins and Enzymes

Frequenin is a Ca2+ binding protein implicated in the regulation of neurotransmitter release at the neuromuscular junction. Frequenin amino acid sequences from different species appear closely related. In mouse a single 4.2 kbp mRNA is produced yielding a protein of 22 kDa when assayed by SDS-PAGE under reducing conditions. Frequenin may colocalize with the dendritic marker MAP-2 and is widely distributed in the brain, spinal cord and dorsal root ganglia. In Drosophila frequenin is related to recoverin and visinin and functions like Ca2+-sensitive guanylyl cyclase activator.