The expanding spectrum of human coronin 1A deficiency.

[severe combined immunodeficiency]

Since the first discovery of coronin in the amoeba Dictyostelium discoideum , remarkable insights have been gained regarding the structure and function of coronins , highly conserved from yeast to humans . It has been speculated that coronins have evolved from actin-binding molecules in lower eukaryotes to regulators of various cellular processes in mammals . Indeed , coronins are not only involved in cytokinesis , cell motility , and other actin-related processes but they are also implicated in immune homeostasis and calcium -calcineurin signaling . Most strikingly , coronin 1 deficiencies give rise to immune deficiencies in mice and humans that are characterized by severe T lymphocytopenia . Whereas complete absence of coronin 1 A is associated with severe combined immunodeficiency in humans , hypomorphic mutations lead to a profound defect in naïve T cells , expansion of oligoclonal memory T cells , and exquisite susceptibility to EBV-associated B cell lymphoproliferation . Recent publications show that coronin 1 A also plays a role in natural killer cell cytotoxic function and in neurobehavioral processes . It can be expected that future identification of coronin 1 A-deficient patients will further extend the phenotypic spectrum thereby increasing our knowledge of this fascinating molecule .