UROP Project

Defining how phosphorylation regulates α-actinin-2 structure, F-actin binding, and actomyosin mechanics

Bioengineering and biomedical engineering, Biological Sciences, Biochemistry, Structural Biology, Sarcomeric Proteins, Recombinant Proteins, Protein Chemistry, α-actinin-2, Actin-Binding Proteins, Muscle Mechanics, Post-Translational Modifications

Research Mentor: Dr. Helene Tigro, She/Her
Department, College, Affiliation: Florida State University, Education, Health, and Human Sciences
Contact Email: ht24@fsu.edu
Research Assistant Supervisor (if different from mentor): Dr. Christopher Solis He/His
Research Assistant Supervisor Email: csolis@fsu.edu
Faculty Collaborators:
Faculty Collaborators Email:

Looking for Research Assistants: Yes
Number of Research Assistants: 2
Relevant Majors: Biochemistry, Neuroscience, Chemistry, Biology, Computational Biology, Engineering
Project Location: On FSU Main Campus
Research Assistant Transportation Required:
Remote or In-person: In-person
Approximate Weekly Hours: 10 hours, During business hours
Roundtable Times and Zoom Link:

• Day: Wednesday, September 2
  Start Time: 1:00
  End Time: 2:30
  Zoom Link: https://fsu.zoom.us/j/98918911622

Project Description

α-Actinin-2 (ACTN2) is a major structural component of the cardiac sarcomere that crosslinks filamentous actin (F-actin) and anchors signaling proteins at the Z-disc, thereby maintaining sarcomere organization and mechanical integrity. Phosphoproteomic studies have identified several mechanically responsive phosphorylation sites within its actin-binding domain (ABD), including T43, S50, S147, and T237. These residues localize near the interface between the tandem calponin homology domains (CH1 and CH2), which regulate transitions between closed (autoinhibited) and open (actin-binding competent) conformations.
Our preliminary computational (Tigro et al., 2026) and biochemical studies suggest that phosphorylation promotes ABD opening, remodels electrostatic interactions, and enhances F-actin binding. These structural changes may influence cytoskeletal organization, actomyosin mechanics, and cardiac function. However, the molecular mechanisms linking phosphorylation-dependent remodeling to α-actinin-2 function remain poorly understood. This project will characterize wild-type and phosphomimetic α-actinin-2 variants using complementary structural and biochemical approaches.

Research Tasks: The student will conduct a literature review on α-actinin-2 biology and phosphorylation-dependent regulation of the cardiac cytoskeleton. Research activities will include recombinant expression and purification of wild-type and phosphomimetic full-length α-actinin-2 variants, actin and myosin purification, SDS-PAGE and native PAGE analysis, F-actin co-sedimentation assays, and in vitro motility assays to assess effects on actin binding, protein conformation, and actomyosin mechanics. Statistical analysis, data interpretation, and figure preparation, will also be performed.

Skills that research assistant(s) may need: Good theoretical understanding of chemistry and biology. Interest in protein biochemistry, structural biology, muscle physiology, and cardiovascular research. Experience with laboratory techniques is helpful but not required. Experience with data analysis, statistics, microscopy, or molecular visualization software such as ChimeraX is beneficial but not required. Strong organizational, time-management, and communication skills, along with the ability to work independently and as part of a team, are highly valued. Motivation to learn new experimental and computational techniques is expected.