Myosin XVIIIA (MYO18A)

Myo18a-alpha contains a KE-rich region, an N-terminal PDZ domain, and a characteristic myosin homology region of head, neck (with 1 IQ motif), and coiled-coil tail. The Myo18a-beta isoform lacks the KE-rich region and PDZ domain. Myo18A-alpha is present in most tissues, while Myo18A-beta is expressed specifically in hematopoietic tissues and cell lines. Myo18a-alpha and Myo18a-beta as 230- and 190-kD proteins, respectively.

Myo18a-alpha colocalizes with the ER-Golgi complex and with membrane ruffles and filopodia, while Myo18a-beta localizes diffusely to the cytoplasm. Myo18a-alpha is expressed in mature but not immature macrophages. MYO18A localizes to the surface of COS-1 cells, and that MYO18A expression in COS-1 cells mediates SPA binding.