ArticleBiophysical journal1995
Trypsin increases availability and open probability of cardiac L-type Ca2+ channels without affecting inactivation induced by Ca2+.
Article in Biophysical journal, 1995. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers.
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Who cites it
12 citing papers in PubMed, 28 citations in OpenAlex.
- The Cav1.2 N terminus contains a CaM kinase site that modulates channel trafficking and function.Pflugers Archiv : European journal of physiology · 2015Article
- Colonic inflammation alters Src kinase-dependent gating properties of single Ca2+ channels via tyrosine nitration.American journal of physiology. Gastrointestinal and liver physiology · 2010Article
- Voltage-gated rearrangements associated with differential beta-subunit modulation of the L-type Ca(2+) channel inactivation.Biophysical journal · 2004Article
- A syntaxin 1, Galpha(o), and N-type calcium channel complex at a presynaptic nerve terminal: analysis by quantitative immunocolocalization.The Journal of neuroscience : the official journal of the Society for Neuroscience · 2004Article
- Two components of voltage-dependent inactivation in Ca(v)1.2 channels revealed by its gating currents.Biophysical journal · 2003Article
- Molecular determinant for run-down of L-type Ca2+ channels localized in the carboxyl terminus of the 1C subunit.The Journal of physiology · 2000Article
- Regulation of ion channels in myocardial cells and protection of ischemic myocardium.Heart failure reviews · 2000Review
- Calcium currents in hair cells isolated from semicircular canals of the frog.Biophysical journal · 2000Article
- Intracellular Ca2+ inhibits smooth muscle L-type Ca2+ channels by activation of protein phosphatase type 2B and by direct interaction with the channel.The Journal of general physiology · 1997Article
- Intracellular Ca2+ inactivates L-type Ca2+ channels with a Hill coefficient of approximately 1 and an inhibition constant of approximately 4 microM by reducing channel's open probability.Biophysical journal · 1997Article
- Estimating the number of channels in patch-clamp recordings: application to kinetic analysis of multichannel data from voltage-operated channels.Biophysical journal · 1997Article
- A type 2A phosphatase-sensitive phosphorylation site controls modal gating of L-type Ca2+ channels in human vascular smooth-muscle cells.The Biochemical journal · 1996Article
Corrections and comments
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Authors and funding
5 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The patch-clamp technique was employed to investigate the response of single L-type Ca2+ channels to the protease trypsin applied to the intracellular face of excised membrane patches from guinea pig ventricular myocytes. Calpastatin and ATP were used to prevent run-down of Ca2+ channel activity monitored with 96 mM Ba2+ as charge carrier in the presence of 2.5 microM (-)-BAYK 8644. Upon application of trypsin (100 micrograms/ml) channel activity was enhanced fourfold and remained elevated upon removal of trypsin, as expected of a proteolytic, irreversible modification. The trypsin effect was not mediated by a proteolytic activation of protein kinases, as evidenced by the insensitivity of this effect to protein kinase inhibitors. Trypsin-modified Ca2+ channels exhibited the usual run-down phanomenon upon removal of calpastatin and ATP. In ensemble average currents trypsin-induced changes of channel function are apparent as a threefold increase in peak current and a reduction in current inactivation. At the single channel level these effects were based on about a twofold increase in both Ca2+ channels' availability and open probability. Neither the actual number of channels in the patch nor their unitary conductance as well as reversal potential was changed by trypsin. The Ca(2+)-induced inactivation was not impaired, as judged by a comparable sensitivity of trypsin-modified Ca2+ channels to intracellular Ca2+. Similarly, trypsin treatment did not affect the sensitivity of Ca2+ channels to phenylalkylmine inhibition. The observed alterations in channel function are discussed in terms of possible structural correlates.
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