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Rab25 influences functional Cav1.2 channel surface expression in arterial smooth muscle cells
- Source :
- American journal of physiology. Cell physiology. 310(11)
- Publication Year :
- 2015
-
Abstract
- Plasma membrane-localized CaV1.2 channels are the primary calcium (Ca2+) influx pathway in arterial smooth muscle cells (myocytes). CaV1.2 channels regulate several cellular functions, including contractility and gene expression, but the trafficking pathways that control the surface expression of these proteins are unclear. Similarly, expression and physiological functions of small Rab GTPases, proteins that control vesicular trafficking in arterial myocytes, are poorly understood. Here, we investigated Rab proteins that control functional surface abundance of CaV1.2 channels in cerebral artery myocytes. Western blotting indicated that Rab25, a GTPase previously associated with apical recycling endosomes, is expressed in cerebral artery myocytes. Immunofluorescence Förster resonance energy transfer (immunoFRET) microscopy demonstrated that Rab25 locates in close spatial proximity to CaV1.2 channels in myocytes. Rab25 knockdown using siRNA reduced CaV1.2 surface and intracellular abundance in arteries, as determined using arterial biotinylation. In contrast, CaV1.2 was not located nearby Rab11A or Rab4 and CaV1.2 protein was unaltered by Rab11A or Rab4A knockdown. Rab25 knockdown resulted in CaV1.2 degradation by a mechanism involving both lysosomal and proteasomal pathways and reduced whole cell CaV1.2 current density but did not alter voltage dependence of current activation or inactivation in isolated myocytes. Rab25 knockdown also inhibited depolarization (20–60 mM K+) and pressure-induced vasoconstriction (myogenic tone) in cerebral arteries. These data indicate that Rab25 is expressed in arterial myocytes where it promotes surface expression of CaV1.2 channels to control pressure- and depolarization-induced vasoconstriction.
- Subjects :
- 0301 basic medicine
Male
Proteasome Endopeptidase Complex
Calcium Channels, L-Type
Physiology
Cerebral arteries
Myocytes, Smooth Muscle
Transfection
Cav1.2
Muscle, Smooth, Vascular
Membrane Potentials
Rats, Sprague-Dawley
03 medical and health sciences
medicine
Myocyte
Animals
Cells, Cultured
Gene knockdown
biology
Voltage-dependent calcium channel
Depolarization
Cell Biology
Cerebral Arteries
Molecular biology
Cell biology
Protein Transport
030104 developmental biology
Vasoconstriction
rab GTP-Binding Proteins
Proteolysis
biology.protein
Call for Papers
RNA Interference
Rab
medicine.symptom
Lysosomes
Signal Transduction
Subjects
Details
- ISSN :
- 15221563
- Volume :
- 310
- Issue :
- 11
- Database :
- OpenAIRE
- Journal :
- American journal of physiology. Cell physiology
- Accession number :
- edsair.doi.dedup.....bfe72b1678c065d29158a4ec4a20cdaf