Research Symposium

BIO

My name is Michelle Rodriguez and I am a Biological Sciences major with a Chemistry Minor. I am from Miami Florida and hope to become a Certified Anesthesiologist Assistant in the future.

Effects of the N-Helix 2-12 Deletion Mutation in Cardiac Troponin C on Myofilament Function

Abstract

For the past 75 years, since the Framingham Study
began, cardiovascular disease (CVD) research has been
pivotal in combating one of the deadliest epidemics in
American history. Many CVDs involve genetic mutations
of proteins within the functional unit of cardiac muscle,
the sarcomere. Cardiomyopathy, specifically
hypertrophic, is characterized by different mutations
that cause enlarged ventricular walls, blocked aortic
flow, abnormal ejection fraction, and many other
cardiac maladaptation. To explore this, we are looking
to evaluate how cardiac troponin C (cTnC), specifically
with the “2-12 del” N-helix deletion mutation, affects
myofilament function. This is important because cTnC
plays a central role in excitation-contraction coupling,
and several amino acids within the N-helix can be
affected by mutations, leading to cardiomyopathy. To
do this, we are extracting endogenous cTnC protein
from skinned cardiac papillary muscle and
reconstituting their sarcomeres with either exogenous
wildtype (control) or N-helix 2-12 del mutated
protein. We expect ~80% of the endogenous protein to
be extracted by CDTA treatment. Following
reconstitution, we measure biomechanical properties
including Ca2+-activated steady-state isometric force
and stiffness, and tension redevelopment kinetics
(kTR). In addition to biomechanics, we plan to perform
Western blots on the experimental tissue to examine
protein composition after extraction-reconstitution. We
anticipate seeing differences in the Ca2+-dependence
of biomechanical properties due to removal of the Nhelix

Keywords: cardiomyopathy, troponin, muscle contraction, cardiac muscle