Chandrasekar Lab

Chandrasekar

Primary research focus

Indra Chandrasekar, PhD

Chandrasekar lab’s research interest is to understand the role of cytoskeletal proteins in cell and organ function. The Chandrasekar research laboratory is trying to answer some fundamental questions in cellular trafficking pathways and extend those findings to organ function and human diseases. The primary focus of the cell-organ function relationships is aimed at the disorders of kidney and the brain. Our research will (hopefully) uncover some novel cellular and molecular mechanisms involved in chronic kidney diseases and neurodegenerative disorders that will facilitate development of future targeted therapies.
  • Associate Scientist
  • Assistant Professor at the University of South Dakota
  • Assistant Professor at South Dakota State University

Sanford Research - Chandrasekar Lab

Behind the research

Cells have compartmentalized structures and rely on regulated membrane trafficking to move cargo between organelles/compartments. Many essential cellular processes such as nutrient uptake, receptor mediated signaling and synaptic vesicle recycling depend on membrane trafficking and endocytosis. Our lab is interested in the role of actin cytoskeleton and actin associated proteins in membrane trafficking and endocytic mechanisms in cells. Recently, we demonstrated that nonmuscle myosin II (MII), an actin associated motor protein is critical for both compensatory and constitutive receptor mediated endocytosis in neurons and fibroblasts. Our work provided the first cellular and genetic evidence for the importance of actin-MII interactions during early stages of clathrin coated vesicle formation. Our current model is that MII regulates endocytosis by forming a contractile network with actin, around the site of membrane remodeling and acting like a purse string to regulate the curvature and scission processes, thereby aiding in vesicle budding (Fig.1). Identifying MII as a critical player in endocytosis has raised the following questions:

 
  1. Does actin-MII play a central role in all types of membrane trafficking events?
     
  2. What are the mechanisms by which MII participates and selectively regulates this crucial cellular process?
     
  3. What are the physiological consequences of loss of actin-MII mediated membrane trafficking in vertebrate systems?
Our work on primary neurons indicates that MII-driven tension/actin dynamics regulate the major pathway of synaptic vesicle retrieval (clathrin mediated compensatory endocytosis) and is critical for synaptic transmission. This suggests a unique and essential role for actin-MII mediated tension in cell types that require rapid and continuous membrane remodeling to perform essential organ function. We are interested in understanding the cell type specific requirements for dynamic cytoskeletal changes in cells that populate organs like kidney and brain.
 
Chandrasekar Lab - MII in CME
Fig.1: Model showing the role of MII in clathrin mediated endocytosis (CME). Actin polymerization drives the vesicle away from the plasma membrane through its interaction with the clathrin coat (mediated by Hip1R) (upward black arrow). Simultaneously, MIIB bipolar filaments contract, producing tension on the actin network associated with the coated pit, arranged parallel to the plasma membrane. The interaction of this actin with dynamin directly or through cortactin produces a purse string-like tightening of the neck and a shearing action orthogonal to the direction of vesicle movement (horizontal black arrow), facilitating scission, invagination, curvature generation and symmetry of clathrin coated pit during CME. Pre-peer reviewed version of Chandrasekar et al, Traffic. 2014 Apr;15(4):418-32.
Resources Positions Available
Access Dr. Chandrasekar's publications here. Please contact Dr. Chandrasekar if you are interested in actin dynamics, membrane-cytoskeletal interactions, and cell - organ function relationship.
Meet members of the Chandrasekar lab here.

 

Contact Information
Telephone: (605) 312-6412
Email: indra.chandrasekar@sanfordhealth.org

 

Lab News

December 2015, Dr. Indra Chandrasekar is a co-author on a recent publication in the journal Molecular Biology of the Cell entitled “Nerve growth factor stimulates axon outgrowth through negative regulation of growth cone actomyosin restraint of microtubule advance.”

October 2015, Dr. Indra Chandrasekar received the O’Brien Fellowship from NIH-George M. O’Brien Center for Advanced Renal Microscopic Analysis at Indiana Center for Biological Microscopy.

October 2015, Phuong Pham, a 2015 NSF-REU scholar in the laboratory of Dr. Chandrakar, presented her Sanford research project at the Council for Undergraduate Research’s Research Experiences for Undergraduates 2015 Symposium in Arlington, VA. The title of her presentation, coauthored by Sanford’s Steve Ortmeier and Dr. Chandrakar, was “Coordinated Functions of Nonmuscle Myosin II and Membrane Remodeling Proteins in Clathrin-Mediated Endocytosis.”