Similarities between oocytes and macrophages. An overview

Abstract

Oocytes behave as macrophages as they internalize solid and liquid substances required for their growth and competence. This activity is more pronounced in lower invertebrates. The slowing of endocytic activity may be caused by constraints imposed by surrounding nurse cells and by the amount of accumulated yolk precursors. The genes concerned with endocytic activity in oocytes are controlled by a negative feedback signal provided by accumulated yolk and/or by signal transduction.

The apoptotic engulfment protein Ced-6 participates in clathrin-mediated yolk uptake inDrosophilaegg chambers

“…Similarly, in C. elegans CED-6 operates with the “eat me” signal receptor CED-1 (Yu et al , 2008; Figure 10) in a partially redundant pathway parallel to CED-2/CrkII, CED-5/Dock180, and CED-12/ELMO (Kinchen et al , 2005), which is upstream of the actin-regulating small GTPase CED-10 (Rac). Invertebrate oocytes can be actively phagocytic and display some similarities with macrophages (Mishra, 2011). Ced-6 could conceivably then act in both endocytosis and phagocytosis in fly eggs, but the germline cysts of higher invertebrates are enveloped by a barrier somatic follicular epithelium.…”