Renaming the 'OS-D/CSP' Family (Part 2): '4-Cysteine Soluble Proteins' (4CSPs)-Intracellular Functions.

The gut, brain, fat body, and various glands, although rich in "CSPs", are not involved in chemosensory functions. We propose renaming the "CSPs" to "4CSPs" (4-Cysteine Soluble Proteins) to clarify their role, avoiding confusion with proteins also found in wings, hemolymph, and eggs. This report highlights studies related to insecticide resistance and lipid transport and expands on potential intracellular functions, strongly indicating non-chemosensory features of 4CSPs. Additionally, we show a significant correlation between 4CSPs and mucins, translation initiation factors, and actin complex proteins, reinforcing the proposal to rename "CSPs" and consider developmental pattern, tissue distribution, and intracellular localization.