PMID- 10377337
OWN - NLM
STAT- MEDLINE
DCOM- 19990715
LR  - 20191023
IS  - 0270-6474 (Print)
IS  - 0270-6474 (Linking)
VI  - 19
IP  - 13
DP  - 1999 Jul 1
TI  - Molecular basis for the inactivation of Ca2+- and voltage-dependent BK channels
      in adrenal chromaffin cells and rat insulinoma tumor cells.
PG  - 5255-64
AB  - Large-conductance Ca2+- and voltage-dependent potassium (BK) channels exhibit
      functional diversity not explained by known splice variants of the single Slo
      alpha-subunit. Here we describe an accessory subunit (beta3) with homology to
      other beta-subunits of BK channels that confers inactivation when it is
      coexpressed with Slo. Message encoding the beta3 subunit is found in rat
      insulinoma tumor (RINm5f) cells and adrenal chromaffin cells, both of which
      express inactivating BK channels. Channels resulting from coexpression of Slo
      alpha and beta3 subunits exhibit properties characteristic of native inactivating
      BK channels. Inactivation involves multiple cytosolic, trypsin-sensitive domains.
      The time constant of inactivation reaches a limiting value approximately 25-30
      msec at Ca2+ of 10 microM and positive activation potentials. Unlike Shaker
      N-terminal inactivation, but like native inactivating BK channels, a cytosolic
      channel blocker does not compete with the native inactivation process. Finally,
      the beta3 subunit confers a reduced sensitivity to charybdotoxin, as seen with
      native inactivating BK channels. Inactivation arises from the N terminal of the
      beta3 subunit. Removal of the beta3 N terminal (33 amino acids) abolishes
      inactivation, whereas the addition of the beta3 N terminal onto the beta1 subunit
      confers inactivation. The beta3 subunit shares with the beta1 subunit an ability 
      to shift the range of voltages over which channels are activated at a given Ca2+.
      Thus, the beta-subunit family of BK channels regulates a number of critical
      aspects of BK channel phenotype, including inactivation and apparent Ca2+
      sensitivity.
FAU - Xia, X M
AU  - Xia XM
AD  - Department of Anesthesiology, Washington University School of Medicine, St.
      Louis, Missouri 63110, USA.
FAU - Ding, J P
AU  - Ding JP
FAU - Lingle, C J
AU  - Lingle CJ
LA  - eng
GR  - R01 DK046564/DK/NIDDK NIH HHS/United States
GR  - DK46564/DK/NIDDK NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Neurosci
JT  - The Journal of neuroscience : the official journal of the Society for
      Neuroscience
JID - 8102140
RN  - 0 (Kcnma1 protein, rat)
RN  - 0 (Large-Conductance Calcium-Activated Potassium Channel alpha Subunits)
RN  - 0 (Large-Conductance Calcium-Activated Potassium Channel beta Subunits)
RN  - 0 (Large-Conductance Calcium-Activated Potassium Channels)
RN  - 0 (Potassium Channel Blockers)
RN  - 0 (Potassium Channels)
RN  - 0 (Potassium Channels, Calcium-Activated)
RN  - 0 (RNA, Messenger)
RN  - 115422-61-2 (Charybdotoxin)
RN  - 21306-56-9 (QX-314)
RN  - 98PI200987 (Lidocaine)
RN  - EC 3.4.21.4 (Trypsin)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Adrenal Glands/*cytology
MH  - Amino Acid Sequence
MH  - Animals
MH  - Calcium/pharmacology
MH  - Charybdotoxin/pharmacology
MH  - Chromaffin Cells/drug effects/*metabolism
MH  - Cytosol/metabolism
MH  - Expressed Sequence Tags
MH  - Gene Expression
MH  - Humans
MH  - Insulinoma/*metabolism/pathology
MH  - *Ion Channel Gating/drug effects
MH  - Large-Conductance Calcium-Activated Potassium Channel alpha Subunits
MH  - Large-Conductance Calcium-Activated Potassium Channel beta Subunits
MH  - Large-Conductance Calcium-Activated Potassium Channels
MH  - Lidocaine/analogs & derivatives/pharmacology
MH  - Molecular Sequence Data
MH  - Oocytes/metabolism/physiology
MH  - Potassium Channel Blockers
MH  - Potassium Channels/chemistry/genetics/*physiology
MH  - *Potassium Channels, Calcium-Activated
MH  - RNA, Messenger/analysis/genetics/metabolism
MH  - Rats
MH  - Sequence Homology, Amino Acid
MH  - Trypsin/metabolism
MH  - Tumor Cells, Cultured
MH  - Xenopus laevis
PMC - PMC6782330
EDAT- 1999/06/23 00:00
MHDA- 1999/06/23 00:01
CRDT- 1999/06/23 00:00
PHST- 1999/06/23 00:00 [pubmed]
PHST- 1999/06/23 00:01 [medline]
PHST- 1999/06/23 00:00 [entrez]
PST - ppublish
SO  - J Neurosci. 1999 Jul 1;19(13):5255-64.