Reassessment of the roles of coronin proteins as actin effectors and in signalling

How, exactly, coronin proteins exert their function is debated. On the one hand, coronins are widely considered as F-actin-binding and regulatory proteins.

On the other hand, coronin proteins were also shown to act as regulators of cAMP/Ca2+ signalling. Here, we demonstrate that endogenously expressed mammalian coronin 1, 2 and 3 did not depend on F-actin for their subcellular localisation and did not impact actin-related processes that were previously reported to be coronin-dependent. We also show that the fusion of GFP or FLAG-tags to coronin proteins resulted in their increased colocalisation with actin and phenocopied loss-of-function mutation in mice.