New research findings to help understand endocytosis better

Hyderabad: Researchers at the CSIR-Centre for Cellular and Molecular Biology (CCMB) here have shed new light on understanding endocytosis. The findings can help in treating depression better, according to a CCMB release.

Endocytosis is the process by which a living cell takes up molecules bound to its surface. It is a key event in the therapeutic action of many of the drugs that act via GPCRs, the release said. G protein-coupled receptors (GPCRs) are tiny cellular nano machines, housed in thin fluid-like cell membranes that separate cells from each other.

They help in communication between the exterior and interior of the cell. Due to their major role in cellular signalling, GPCRs represent prominent drug targets, it said. GPCRs are known to enter the inside of cells by the process of endocytosis. However, the details of regulation of endocytosis and the route the receptors follow during the process is still not fully understood, it said. In a recent finding published in the American Chemical Society journal 'Biochemistry,' Amitabha Chattopadhyays group from the CSIR-CCMB sheds some light on this, it said.

"The researchers have identified the molecular players involved in endocytosis of an important member of the GPCR family, the serotonin receptor," it said. The serotonin receptor is an important drug target in neuropsychiatric disorders such as anxiety and depression, it said.

"Prof Chattopadhyay's group showed that these receptors enter the cellular interior through specialised regions of the cell membrane, called clathrin coated pits," it said. "We probed the receptor's movement within the cell, and found that it eventually recycles back to the cell membrane," the release quoted G Aditya Kumar, a PhD student and the first author of the paper, as saying.

The novel findings from the CCMB group enhance fundamental understanding of molecular events leading to endocytosis of GPCRs, it said. They could also provide significant insights into the underlying mechanism of anti-depressants such as the commonly prescribed class of anti-depressant drugs called Selective Serotonin Reuptake Inhibitors (SSRIs).

This is especially relevant in the Indian context since it has been reported by the National Mental Health Survey (2015-16) that more than five per cent of the Indian population over 18 years of age suffer from depression, the release said.

"We are now exploring how the route of endocytosis changes in different types of cells with varying lipid content, thereby raising the prospect of cell-specific endocytosis," Chattopadhyay said.