RAB-35 regulates distinct steps of trogocytosis in the biting and bitten cell

Area of Science:

• Cell Biology
• Developmental Biology
• Genetics

Background:

• Trogocytosis is a cellular process where one cell consumes parts of another.
• Understanding the molecular mechanisms of trogocytosis is crucial for developmental processes.
• A specific trogocytosis event occurs in *C. elegans* involving endodermal cells and primordial germ cells (PGCs).

Purpose of the Study:

• To investigate the molecular mechanisms underlying a programmed trogocytosis event in *C. elegans*.
• To identify key regulators of this specific cellular cannibalism process.
• To elucidate the distinct roles of identified regulators in both the 'biting' and 'bitten' cells.

Main Methods:

• Conducted a genetic screen in *C. elegans* to identify genes involved in trogocytosis.
• Utilized molecular and cellular biology techniques to analyze the function of identified genes.
• Investigated the localization and function of RAB-35 in both endodermal and PGCs.

Main Results:

• Identified the Rab family GTPase *rab-35* as a central regulator of trogocytosis.
• RAB-35 functions in both the endodermal (biting) and PGC (bitten) cells.
• In endodermal cells, RAB-35 promotes PGC lobe digestion by removing PIP₂.
• In PGCs, RAB-35 works with the ESCRT complex to facilitate lobe scission.

Conclusions:

• Discovered RAB-35 as a novel regulator of trogocytosis with dual roles in distinct cell types.
• Demonstrated that the 'bitten' cell actively participates in the scission of its own membrane fragments.
• Provided new insights into the complex molecular machinery governing cellular cannibalism during development.