title: Differential interaction of β2e with phosphoinositides: A comparative study between β2e and MARCKS.
abstract: Voltage-gated calcium (CaV) channels are responsible for Ca(2+) influx in excitable cells. As one of the auxiliary subunits, the CaV β subunit plays a pivotal role in the membrane expression and receptor modulation of CaV channels. In particular, the subcellular localization of the β subunit is critical for determining the biophysical properties of CaV channels. Recently, we showed that the β2e isotype is tethered to the plasma membrane. Such a feature of β2e is due to the reversible electrostatic interaction with anionic membrane phospholipids. Here, we further explored the membrane interaction property of β2e by comparing it with that of myristoylated alanine-rich C kinase substrate (MARCKS). First, the charge neutralization of the inner leaf of the plasma membrane induced the translocation of both β2e and MARCKS to the cytosol, while the transient depletion of poly-phosphoinositides (poly-PIs) by translocatable pseudojanin (PJ) systems induced the cytosolic translocation of β2e but not MARCKS. Second, the activation of protein kinase C (PKC) induced the translocation of MARCKS but not β2e. We also found that after the cytosolic translocation of MARCKS by receptor activation, depletion of poly-PIs slowed the recovery of MARCKS to the plasma membrane. Together, our data demonstrate that both β2e and MARCKS bind to the membrane through electrostatic interaction but with different binding affinity, and thus, they are differentially regulated by enzymatic degradation of membrane PIs.
authors.affiliation: a Department of Brain and Cognitive Sciences, DGIST , Daegu , Korea.
authors.forename: Dong-Il
authors.initials: DI
authors.lastname: Kim
authors.affiliation: a Department of Brain and Cognitive Sciences, DGIST , Daegu , Korea.
authors.forename: Byung-Chang
authors.initials: BC
authors.lastname: Suh
mesh_terms: D000595:Amino Acid Sequence; D015220:Calcium Channels / Q000737:chemistry* / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010716:Phosphatidylinositols / Q000378:metabolism*; D011485:Protein Binding; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism*; D055672:Static Electricity
chemical_list: D015220:Calcium Channels; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D010716:Phosphatidylinositols; D021122:Protein Subunits; D000076250:Myristoylated Alanine-Rich C Kinase Substrate
keywords: electrostatic interaction; myristoylated alanine-rich C kinase substrate (MARCKS); phosphatidylinositol 4,5-bisphosphate (PIP2); protein kinase C (PKC); voltage-gated calcium channel; β2e subunit