Dr. David Barefield gives an in-depth discussion on his research investigating the role of the MyBP-HL protein in atrial dysfunction.

Myosin binding protein H-like (MyBP-HL) is an atrial myofilament protein that establishes a stoichiometry with cardiac myosin binding protein-C (cMyBP-C). Loss of MyBP-HL leads to atrial dilation, arrhythmia, and dilated cardiomyopathy. Several human MYBPHL nonsense variants are reported in the gnomAD database.

The Barefield Lab asked whether nonsense variants prevent MyBP-HL incorporation into the myofilament, or if truncation variants result in alternative protein localization within the cardiomyocyte. Neonatal rat cardiomyocytes were isolated and transfected with wild-type mouse Mybphl or mouse Mybphl that had human MYBPHL nonsense mutations. Immunofluorescence confocal microscopy showed wild-type mouse MyBP-HL colocalized with cMyBP-C. The W54X, R133X, W158X, W192X, K250X, and R255X variants all failed to co-localize.

As the MYBPHL stop variants prevented myofilament binding, the Barefield Lab performed biophysical experiments on single myofibrils isolated from Mybphl null mice. Mybphl null myofibrils showed significantly faster phase of linear relaxation. These data show that MYBPHL premature stop variants do not encode functional proteins and loss of MyBP-HL causes biophysical defects in atrial myofibrils.

Key Topics Include:

  • Myosin binding protein H-like competes for thick filament binding with cardiac myosin binding protein-C.
  • Nonsense variants in MYBPHL result in truncated proteins that do not incorporate into the atrial sarcomere.
  • Mice lacking myosin binding protein H-like have an accelerated linear phase of myofibril relaxation.
Click to watch the webinar recording. To view the presentation full screen simply click the square icon located in the bottom-right corner of the video-viewer.


To retrieve a PDF copy of the presentation, click on the link below the slide player. From this page, click on the “Download” link to retrieve the file.


Assistant Professor
Cell and Molecular Physiology
Loyola University Chicago

Dr. David Barefield is an Assistant Professor at Loyola University Chicago. The Barefield Lab opened in May 2020 and focuses on atrial myopathies and the role of atrial dysfunction in common forms of cardiovascular disease.

Production Partner

Aurora Scientific, Inc.

Aurora Scientific supports the scientific community in its goal of research and discovery by providing precision instrumentation of the highest quality design, construction and functionality for Muscle Physiology, Material Science and Neuroscience applications.

Additional Content From Aurora Scientific, Inc.

Setup and Use of the 3-in-1 Whole Animal System

Setup and Use of the 3-in-1 Whole Animal System

The Aurora Scientific team will perform a live virtual demonstration of their 3-in-1 Whole Animal System, using a methodology focused overview of the 3 main experimental techniques for assessing contractility of whole muscle in murine models.
Cut and Paste of Myosin Binding Protein-C in Striated Muscles

Cut and Paste of Myosin Binding Protein-C in Striated Muscles

Dr. Samantha Harris discusses the development of three new mouse models in her lab, engineered to target and replace specific myosin binding protein-C paralogs in muscle fibers and impact of their mutations on skeletal and cardiac muscle diseases.
Integrating Patient Engagement and Trainee Development in Pre-Clinical Research

Integrating Patient Engagement and Trainee Development in Pre-Clinical Research

Christopher Perry, PhD discusses how his laboratory aims to discover mechanisms by which metabolic dysfunction causes muscle weakness and apply these findings to develop new therapies for muscle disorders. Homira Osman, PhD provides a particular focus on leveraging scientific findings for practice and policy and linking trainees with patient communities.

Additional Content From American Physiological Society

Additional Content From European Council for Cardiovascular Research

Cardio-Renal-Lymphatic Disease

Cardio-Renal-Lymphatic Disease

In this webinar, Dr. Giacomo Rossitto shares his research on heart failure and the related lymphatic dysfunction in patients.

Related Content