Indian American researchers make new discoveries on malaria parasite

Souvik Bhattacharjee and Kasturi Haldar

NEW YORK: A team led by two Indian American researchers of the University of Notre Dame has made fundamental discovery in understanding how malaria parasites cause deadly disease.

Kasturi Haldar and Souvik Bhattacharjee of the University’s Center for Rare and Neglected Diseases, show how parasites target proteins to the surface of the red blood cell that enables sticking to and blocking blood vessels, the Notre Dame News reports.

The research findings appear in the Jan 20 edition of the journal Cell, the leading journal in the life sciences. The study was supported by the National Institutes of Health.
Malaria is a blood disease that kills nearly 1 million people each year. It is caused by a parasite that infects red cells in the blood. Once inside the cell, the parasite exports proteins beyond its own plasma membrane border into the blood cell.

These proteins function as adhesins that help the infected red blood cells stick to the walls of blood vessels in the brain and cause cerebral malaria, a deadly form of the disease that kills over half a million children each year.

In all cells, proteins are made in a specialized cell compartment called the endoplasmic reticulum (ER) from where they are delivered to other parts of the cell.

According to the campus publication, Haldar and Bhattacharjee and collaborators Robert Stahelin at the Indiana University School of Medicine-South Bend (who also is an adjunct faculty member in Notre Dame’s Department of Chemistry and Biochemistry), and David and Kaye Speicher at the University of Pennsylvania’s Wistar Institute discovered that for host-targeted malaria proteins the very first step is binding to the lipid phosphatidylinositol 3-phosphate, PIP, in the ER.

Previous studies suggested an enzyme called Plasmepsin V that released the proteins into the ER was also the export mechanism. However, Haldar, Bhattacharjee and colleagues discovered that binding to PIP lipid which occurs first is the gate keeper to control export and that export can occur without Plasmepsin V action.

Further, in higher eukaryotic cells (such as in humans), the lipid PIP is not usually found within the ER membrane but rather is exposed to the cellular cytoplasm, the Notre Dame News says.

Haldar and Bhattacharjee are experts in malaria parasite biology and pathogenesis. Stahelin is an expert in PIP lipid biology, and David and Kaye Speicher are experts in proteomics and a method called mass spectrometry.

Their interdisciplinary collaboration reveals a fundamental, novel cellular function, whose disruption can provide new therapies that are urgently needed for malaria.

India Post News Service

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