Uncoupling of Calcium Channel α1 and β Subunits in Developing Neurons

Abstract Calcium channel β subunits are key modulators of calcium channel function and membrane targeting of the pore-forming α1 subunit. Here we show that an invertebrate (Lymnaea stagnalis) homolog of P/Q- and N-type calcium channels (LCav2), although colocalized with β subunits in synapses of mature neurons, is physically uncoupled from the β subunits in the leading edge of growth cones of outgrowing neurons. Moreover, LCav2 channels that mediate transmitter release in mature synapses also participate in neuronal outgrowth in growth cones. The differential association of β subunits with synaptic calcium channels and those expressed in emergent neuronal growth suggests that β subunits may play a role in the transformation of Cav2 calcium channel function in immature neurons and mature synapses.