科研之友
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摘要
Background: Calcium channels control membrane excitability. The mechanisms underlying Ca(v)2.1/Ca(v)2.2 targeting are not well understood. Results: Ankyrin-B associates with Ca(v)2.1/Ca(v)2.2. Loss of ankyrin-B results in reduced expression of Ca(v)2.1/Ca(v)2.2 in select brain regions. Conclusion: Ankyrin-B plays a role in the expression of Ca(v)2.1/Ca(v)2.2. Significance: Results identify pathway for membrane targeting of calcium channels and regulation of membrane excitability. N-type and P/Q-type calcium channels are documented players in the regulation of synaptic function; however, the mechanisms underlying their expression and cellular targeting are poorly understood. Ankyrin polypeptides are essential for normal integral membrane protein expression in a number of cell types, including neurons, cardiomyocytes, epithelia, secretory cells, and erythrocytes. Ankyrin dysfunction has been linked to defects in integral protein expression, abnormal cellular function, and disease. Here, we demonstrate that ankyrin-B associates with Ca(v)2.1 and Ca(v)2.2 in cortex, cerebellum, and brain stem. Additionally, using in vitro and in vivo techniques, we demonstrate that ankyrin-B, via its membrane-binding domain, associates with a highly conserved motif in the DII/III loop domain of Ca(v)2.1 and Ca(v)2.2. Further, we demonstrate that this domain is necessary for proper targeting of Ca(v)2.1 and Ca(v)2.2 in a heterologous system. Finally, we demonstrate that mutation of a single conserved tyrosine residue in the ankyrin-binding motif of both Ca(v)2.1 (Y797E) and Ca(v)2.2 (Y788E) results in loss of association with ankyrin-B in vitro and in vivo. Collectively, our findings identify an interaction between ankyrin-B and both Ca(v)2.1 and Ca(v)2.2 at the amino acid level that is necessary for proper Ca(v)2.1 and Ca(v)2.2 targeting in vivo.
- 出版日期2014-2-21
