Association and colocalization of the Kvbeta1 and Kvbeta2 beta-subunits with Kv1 alpha-subunits in mammalian brain K+ channel complexes.
The differential expression and association of cytoplasmic beta-subunits with pore-forming alpha-subunits may contribute significantly to the complexity and heterogeneity of voltage-gated K+ channels in excitable cells. Here we examined the association and colocalization of two mammalian beta-subunits, Kvbeta1 and Kvbeta2, with the K+ channel alpha-subunits Kv1.1, Kv1.2, Kv1.4, Kv1.6, and Kv2.1 in adult rat brain. Reciprocal coimmunoprecipitation experiments using subunit-specific antibodies indicated that Kvbeta1 and Kvbeta2 associate with all the Kv1 alpha-subunits examined, and with each other, but not with Kv2.1. A much larger portion of the total brain pool of Kv1-containing channel complexes was found associated with Kvbeta2 than with Kvbeta1. Single- and multiple-label immunohistochemical staining indicated that Kvbeta1 codistributes extensively with Kv1.1 and Kv1.4 in cortical interneurons, in the hippocampal perforant path and mossy fiber pathways, and in the globus pallidus and substantia nigra. Kvbeta2 codistributes extensively with Kv1.1 and Kv1.2 in all brain regions examined and was strikingly colocalized with these alpha-subunits in the juxtaparanodal region of nodes of Ranvier as well as in the axons and terminals of cerebellar basket cells. Taken together, these data provide a direct demonstration that Kvbeta1 and Kvbeta2 associate and colocalize with Kv1 alpha-subunits in native tissues and provide a biochemical and neuroanatomical basis for the differential contribution of Kv1 alpha- and beta-subunits to electrophysiologically diverse neuronal K+ currents.
Rhodes
K J
KJ
Central Nervous System Disorders, Wyeth-Ayerst Research, Princeton, New Jersey 08543, USA.
Strassle
B W
BW
Monaghan
M M
MM
Bekele-Arcuri
Z
Z
Matos
M F
MF
Trimmer
J S
JS
D000818:Animals; D015153:Blotting, Western; D001923:Brain Chemistry; D002531:Cerebellum / Q000737:chemistry; D051668:Delayed Rectifier Potassium Channels; D019084:Fluorescent Antibody Technique, Indirect; D005917:Globus Pallidus / Q000737:chemistry; D007124:Immunoenzyme Techniques; D007395:Interneurons / Q000737:chemistry; D051662:Kv1.1 Potassium Channel; D051663:Kv1.2 Potassium Channel; D051665:Kv1.4 Potassium Channel; D019599:Mossy Fibers, Hippocampal / Q000737:chemistry; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000737:chemistry; D009928:Organ Specificity; D019580:Perforant Pathway / Q000737:chemistry; D015221:Potassium Channels / Q000032:analysis* / Q000737:chemistry; D024642:Potassium Channels, Voltage-Gated; D011901:Ranvier's Nodes / Q000737:chemistry; D051381:Rats; D051669:Shab Potassium Channels; D013378:Substantia Nigra / Q000737:chemistry
D051668:Delayed Rectifier Potassium Channels; C496972:Kcna2 protein, rat; C496979:Kcna4 protein, rat; C496991:Kcnb1 protein, rat; D051663:Kv1.2 Potassium Channel; D051665:Kv1.4 Potassium Channel; D009419:Nerve Tissue Proteins; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D051669:Shab Potassium Channels; D051662:Kv1.1 Potassium Channel