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

The gut, brain, fat body, wing, epidermis, corpora allata, salivary gland, pheromone gland, prothoracic gland, and many other tissues are not included in the olfactory/chemosensory function. However, they are the tissues where CSPs are most prevalent, with the exception of the antennae and legs. In part-1, we proposed renaming the "chemosensory protein (CSP)" family to "4-Cysteine Soluble Proteins (4CSPs)" in order to avoid designating a protein present in hemolymph or eggs as chemosensory. In part-2, we broaden the report's focus from ubiquitous tissue distribution to potential intracellular functions in order to bolster our idea. We go over our studies on insecticide resistance, the Mp10 story in aphids, and other systems relevant to lipid transport and immunity. Most of the data gradually tilt toward the non-chemosensory features of 4CSPs, and this adds even more evidence to support those aspects. We provide a second review (part-2) and analysis that shows a stronger association between 4CSPs and mucins, translation initiation factors, and proteins belonging to the actin complex family. This is yet another compelling evidence that the benefits of renaming "chemosensory proteins" far outweigh the drawbacks, when taking tissue distribution and intracellular localization into account.