Expression of a NOS-III-like protein in human astroglial cell culture

Evidence for the presence of a type-III nitric oxide synthase-like protein (NOS-III-like protein) in astroglial cells is reported. The mRNA of a NOS-III-like protein is constitutively expressed in human astrocytoma T67 cells, taken as an astroglial model. The nucleotide sequence of the PCR product (422 bp) shares more than 99% identity with the cDNA (from 1588 to 2009) of the human endothelial nitric oxide synthase (NOS-III). The molecular mass of the astroglial NOS-III-like protein is about 140 kDa, as observed for human NOS-III. Moreover, the astroglial NOS-III-like protein is constitutively tyrosine-phosphorylated and associated with caveolin-1. The astroglial NOS-III-like protein is apparently inactive, as reported for phosphorylated human NOS-III associated with caveolin-1.