Compartmental Volume Regulation of E. Coli under Various Growth Conditions

Abstract

primary cultures of rat superior cervical ganglia (SCG) neurons. The goal is to understand the discernible differences in regulation of trafficking between CaV2 subtypes (CaV2.1, CaV2.2, CaV2.3). Recombinant cDNA of subtypedefining a1 subunit is injected intranuclearly into dissociated SCG neurons. CaV2 membrane expression is evaluated in whole cell patch clamp recordings. We have found that recombinant CaV2.1 and CaV2.3 expression increases current density above uninjected levels, suggesting these subtypes have increased membrane expression. Recombinant CaV2.2 expression does not increase current density beyond uninjected levels, suggesting that CaV2.2 has limited membrane expression. Additionally, pharmacological evidence suggests that recombinant CaV2.1, but not CaV2.3, displaces native CaV2.2. This hierarchy of membrane localization (CaV2.1 > CaV2.2 > CaV2.3) suggests that cells employ a mechanism to regulate and perhaps cap expression levels of specific CaV2 channel subtypes. Immunocytochemistry analysis shows that availability of auxiliary subunits (b4 and a2d1) is not limited. We hypothesize that the trafficking hierarchy is defined by important interactions which are sequence specific.