Identification of a novel smooth muscle associated protein, smap2, upregulated during neointima formation in a rat carotid endarterectomy model.

Proliferation of aortic smooth muscle cells is an important event in vascular lesion formation. To identify new genes that are involved in neointima formation, we constructed an aortic 3'-directed cDNA library. The novel cDNA of a gene designated smooth muscle associated protein 2 (smap2) was isolated. The full-length cDNA of smap2 is 2914 base pairs long and contains an open reading frame of 1338 base pairs. Dot blot analysis revealed that smap2 was expressed particularly in aorta. The deduced amino acid sequence of smap2 contains two thyroglobulin type-1 domains, two EF-hand calcium-binding domains and putative signal peptide. Furthermore, we demonstrated that smap2 mRNA was upregulated during neointima formation in a rat carotid endarterectomy model. These findings suggest that smap2 might be involved in the progression of atherosclerosis in aorta.