In a significant breakthrough, scientists at the CSIR-Centre for Cellular and Molecular Biology (CCMB) in Hyderabad have announced a major discovery: they’ve cracked the code behind how cells precisely adapt their internal ‘skeletons’ to form dynamic protrusions. These fascinating structures are not just for show; they are absolutely crucial for a host of biological processes, including how our bodies fight off pathogens, heal wounds, mount an effective immune response, and unfortunately, even contribute to the progression of cancer.
At the heart of a cell’s ever-changing form lies a dense, branched network called actin, located just beneath its outer membrane. These remarkable actin molecules are incredibly dynamic, constantly working to push against the cell membrane. This pushing action is fundamental; whenever a cell needs to adopt a new shape or extend a protrusion, it must rapidly construct a fresh meshwork of actin, meticulously directed to push in the precise direction required for its function.
Under the leadership of Dr. Saikat Chowdhury, the dedicated team at CCMB made a pivotal finding: cells meticulously control the creation of this new actin mesh using a protein known as SPIN90. Utilizing the advanced capabilities of the cryogenic electron microscope facility, Dr. Chowdhury and his PhD scholar, Justus Francis, meticulously observed and discovered that SPIN90 operates as a dimer, working in conjunction with another crucial protein complex, Arp2/3. This collaborative effort allows cells to form protrusions in multiple directions, orchestrating their complex reshaping.
Justus Francis, the first author of this groundbreaking study, highlighted the significance of their work. “This intricate process offers us a deeper understanding of how cells adapt and remodel themselves, both when they are healthy and when they are affected by disease,” he explained. “Our ability to observe SPIN90’s action with near-atomic resolution was key. It allowed us to unveil the exact molecular mechanism that governs how mammalian cells divide and function right from their earliest developmental stages.” The findings have been proudly published in the prestigious journal, Nature Structural & Molecular Biology.