Seminar: How the Functional Clustering of L-Type Calcium Channels Enhances Excitability in Our Hearts and Minds

Event Details
  • Date/Time:
    • Thursday May 5, 2016
      12:00 pm - 1:00 pm
  • Location: Applied Physiology Building, 555 14th Street NW, Atlanta, GA, Room 1253
  • Phone: (404) 894-7568
  • URL:
  • Email: adrienne.durham@ap.gatech.edu
  • Fee(s):
    N/A
  • Extras:
Contact

Adrienne Durham

Academic Program Coordinator

School of Applied Physiology

Summaries

Summary Sentence: Dr. Marc. D. Binder, professor of physiology and biophysics at the University of Washington will present results refuting long-held views about the behavior of L-type calcium channels.

Full Summary: L-type calcium channels are ubiquitously expressed in excitable cells. They are engaged in a wide range of physiological processes including excitation-contraction coupling in muscle, hormone secretion, gene transcription, and repetitive neural discharge. As is the case for all voltage-gated channels, it is widely assumed that individual L-type calcium channels behave independently with respect to voltage-activation, open probability, and facilitation. In this talk, I will describe the results of super-resolution fluorescent imaging, optogenetic measurements, and electrophysiological measurements that refute this long-held view.  

Media
  • Marc D. Binder Marc D. Binder
    (image/png)

L-type calcium channels are ubiquitously expressed in excitable cells. They are engaged in a wide range of physiological processes including excitation-contraction coupling in muscle, hormone secretion, gene transcription, and repetitive neural discharge.

As is the case for all voltage-gated channels, it is widely assumed that individual L-type calcium channels behave independently with respect to voltage-activation, open probability, and facilitation. In this talk, I will describe the results of super-resolution fluorescent imaging, optogenetic measurements, and electrophysiological measurements that refute this long-held view.

We have found that both the Cav1.2 channel that is expressed predominantly in muscle cells and the Cav1.3 channel that is expressed preferentially in neurons associate in functional clusters of two or more channels that open cooperatively, facilitating Ca2+ influx. Both channel types are coupled via C-terminus-to-C-terminus interactions that require binding of the incoming Ca2+ to calmodulin (CaM) and subsequent binding of CaM to the pre-IQ domain of the channels.

Physically-coupled L-type channels facilitate Ca2+ currents as a consequence of their higher open probabilities, leading to the highly reliable heartbeat observed in cardiac tissue and increased firing rates in neurons.

We propose that cooperative gating of L-type calcium channels represents a novel mechanism for the regulation of Ca2+ signaling and electrical activity.

Additional Information

In Campus Calendar
Yes
Groups

College of Sciences

Invited Audience
Undergraduate students, Faculty/Staff, Public, Graduate students
Categories
Seminar/Lecture/Colloquium
Keywords
Calcium channels, College of Sciences, School of Applied Physiology
Status
  • Created By: A. Maureen Rouhi
  • Workflow Status: Published
  • Created On: Apr 27, 2016 - 4:46am
  • Last Updated: Apr 13, 2017 - 5:15pm