Uncoupling of calcium channel α1 and β subunits in developing neurons

Calcium channel beta subunits are key modulators of calcium channel function and membrane targeting of the pore-forming alpha(1) subunit. Here we show that an invertebrate (Lymnaea stagnalis) homolog of P/Q- and N-type calcium channels (LCa(v)2), although colocalized with beta subunits in synapses of mature neurons, is physically uncoupled from the beta subunits in the leading edge of growth cones of outgrowing neurons. Moreover, LCa(v)2 channels that mediate transmitter release in mature synapses also participate in neuronal outgrowth in growth cones. The differential association of beta subunits with synaptic calcium channels and those expressed in emergent neuronal growth suggests that beta subunits may play a role in the transformation of Ca(v)2 calcium channel function in immature neurons and mature synapses.