[HTML][HTML] Proteolytic processing of the L-type Ca 2+ channel alpha 11.2 subunit in neurons
OR Buonarati, PB Henderson, GG Murphy… - …, 2017 - ncbi.nlm.nih.gov
Background: The L-type Ca2+ channel Cav1. 2 is a prominent regulator of neuronal
excitability, synaptic plasticity, and gene expression. The central element of Cav1. 2 is the
pore-forming α 1 1.2 subunit. It exists in two major size forms, whose molecular masses have
proven difficult to precisely determine. Recent work suggests that α 1 1.2 is proteolytically
cleaved between the second and third of its four pore-forming domains (Michailidis et al,.
2014). Methods: To better determine the apparent molecular masses (MR) of the α 1 1.2 size …
excitability, synaptic plasticity, and gene expression. The central element of Cav1. 2 is the
pore-forming α 1 1.2 subunit. It exists in two major size forms, whose molecular masses have
proven difficult to precisely determine. Recent work suggests that α 1 1.2 is proteolytically
cleaved between the second and third of its four pore-forming domains (Michailidis et al,.
2014). Methods: To better determine the apparent molecular masses (MR) of the α 1 1.2 size …
Abstract
Background: The L-type Ca2+ channel Cav1. 2 is a prominent regulator of neuronal excitability, synaptic plasticity, and gene expression. The central element of Cav1. 2 is the pore-forming α 1 1.2 subunit. It exists in two major size forms, whose molecular masses have proven difficult to precisely determine. Recent work suggests that α 1 1.2 is proteolytically cleaved between the second and third of its four pore-forming domains (Michailidis et al,. 2014).
Methods: To better determine the apparent molecular masses (M R) of the α 1 1.2 size forms, extensive systematic immunoblotting of brain tissue as well as full length and C-terminally truncated α 1 1.2 expressed in HEK293 cells was conducted using six different region–specific antibodies against α 1 1.2.
Results: The full length form of α 1 1.2 migrated, as expected, with an apparent M R of~ 250 kDa. A shorter form of comparable prevalence with an apparent M R of~ 210 kDa could only be detected in immunoblots probed with antibodies recognizing α 1 1.2 at an epitope 400 or more residues upstream of the C-terminus.
Conclusions: The main two size forms of α 1 1.2 are the full length form and a shorter form, which lacks~ 350 distal C-terminal residues. Midchannel cleavage as suggested by Michailidis et al.(2014) is at best minimal in brain tissue.
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