The Active Role of Corpse Engulfment Pathways During Cell Competition

Abstract

Cell competition was first described in imaginal discs of genetically-mosaic Drosophila. In extreme cases, cell competition can replace entire compartments with the descendents of a single cell. We recently identified five genes that are required by wild-type epithelial cells to kill neighboring Minute cells during cell competition. These draper, wasp, phosphatidyl-serine receptor, MBC/DOCK180 and Rac1 genes, were each previously implicated in the engulfment of apoptotic corpses. The results draw attention to the active, killing role of engulfing cells during cell competition. Here we discuss the contributions of these engulfment genes to Minute competition in more detail, and compare Minute competition with competition between cells expressing different levels of Myc, or of Warts pathway genes. We also speculate about how cell interactions at clone boundaries may initiate cell competition.

Oriented Cell Division as a Response to Cell Death and Cell Competition

“…It is not known at present how cells sense nearby apoptosis. Possible mechanisms include alterations in Fat or Ds activity levels in dying cells, which would have non -autonomous effects [12], expression of growth factors by dying cells [9], cell polarization in the course of engulfing dead cell fragments [25], or mechanical stretching of the epithelium when cell numbers are reduced [26]. PCP proteins could sense one or more such signal and define the polarized cellular response; alternatively, PCP genes might be necessary to implement a polarity that is sensed by other proteins.…”

The Naïve B Cells are the Lymphocytes with the Highest Anionic Phospholipid Binding Ratios

“…CD14 was involved in the recognition and phagocytosis of cells undergoing apoptosis [32]. A protein receptor on the surface of macrophages, fibroblasts and epithelial cells for phosphatidylserine-specific clearance of apoptotic cells and engulfment of apoptotic corpses was described [9,33]. Phosphatidylserine receptor (PSR) was identified by monoclonal antibodies mAb 217 [9].…”

Cell Competition and Its Possible Relation to Cancer

“…This has been much studied in the nematode C. elegans. The molecular mechanism by which cells are killed by being engulfed is not yet clear (1). Active contributions of engulfment to death has also seen in other circumstances, such as in the assassination of Purkinje neurons by microglia and in certain circumstances in C. elegans (13).…”

“…''Cell competition'' refers more specifically to a phenomenon in which the growth rate is altered by having different neighbors (1). It turns out that the growth properties of cells can depend on who their neighbors are, with cell competition defined by reciprocal increases and decreases in growth on the part of cells juxtaposed in a chimera (Fig.…”