Voltage-gated K+ channel beta subunits: expression and distribution of Kv beta 1 and Kv beta 2 in adult rat brain.
Recent cloning of K+ channel beta subunits revealed that these cytoplasmic polypeptides can dramatically alter the kinetics of current inactivation and promote efficient glycosylation and surface expression of the channel-forming alpha subunits. Here, we examined the expression, distribution, and association of two of these beta subunits, Kv beta 1 and Kv beta 2, in adult rat brain. In situ hybridization using cRNA probes revealed that these beta-subunit genes are heterogeneously expressed, with high densities of Kv beta 1 mRNA in the striatum, CA1 subfield of the hippocampus, and cerebellar Purkinje cells, and high densities of Kv beta 2 mRNA in the cerebral cortex, cerebellum, and brainstem. Immunohistochemical staining using subunit-specific monoclonal and affinity-purified polyclonal antibodies revealed that the Kv beta 1 and Kv beta 2 polypeptides frequently co-localize and are concentrated in neuronal perikarya, dendrites, and terminal fields, and in the juxtaparanodal region of myelinated axons. Immunoblot and reciprocal co-immunoprecipitation analyses indicated that Kv beta 2 is the major beta subunit present in rat brain membranes, and that most K+ channel complexes containing Kv beta 1 also contain Kv beta 2. Taken together, these data suggest that Kv beta 2 is a component of almost all K+ channel complexes containing Kv 1 alpha subunits, and that individual channels may contain two or more biochemically and functionally distinct beta-subunit polypeptides.
Rhodes
K J
KJ
CNS Disorders, Wyeth-Ayerst Research, Princeton, New Jersey 08543, USA.
Monaghan
M M
MM
Barrezueta
N X
NX
Nawoschik
S
S
Bekele-Arcuri
Z
Z
Matos
M F
MF
Nakahira
K
K
Schechter
L E
LE
Trimmer
J S
JS
D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D001921:Brain / Q000378:metabolism*; D004594:Electrophysiology; D007150:Immunohistochemistry; D015640:Ion Channel Gating; D015335:Molecular Probes / Q000235:genetics; D008969:Molecular Sequence Data; D015221:Potassium Channels / Q000235:genetics / Q000502:physiology*; D011233:Precipitin Tests; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D014018:Tissue Distribution
D000911:Antibodies, Monoclonal; D015335:Molecular Probes; D015221:Potassium Channels; D012333:RNA, Messenger