AT LEAST 2 RECEPTORS OF ASYMMETRIC ACETYLCHOLINESTERASE ARE PRESENT AT THE SYNAPTIC BASAL LAMINA OF TORPEDO ELECTRIC ORGAN

Asymmetric acetylcholinesterase (AChE) is anchored to the basal lamina (BL) of cholinergic synapses via its collagenic tail, yet the complem ent of matrix receptors involved in its attachment remains unknown. Th e development of a novel overlay technique has allowed us to identify two Torpedo BL components that bind asymmetric AChE: a polypeptide of similar to 140kDa and a doublet of 195-215kDa. These were found to sta in metachromatically with Coomassie blue R-250, mere solubilized by ac etic acid, and were sensitive to collagenase treatment. Upon sequence analysis, the 140kDa polypeptide yielded a characteristic collagenous motif. Another AChE-binding BL constituent, identified by overlay, cor responded to a heparan sulfate proteoglycan. Lastly, we established th at this proteoglycan, but not the collagenous proteins, interacted wit h at least one heparin binding domain of the collagenic tail of AChE. Our results indicate that at least two BL receptors are likely to exis t for asymmetric AChE in Torpedo electric organ. (C) 1998 Academic Pre ss.