Seung‐Taek Lee

Abnormalities of the P gene are associated with a wide range of clinical phenotypes, including type II oculocutaneous albinism, albinism associated with the Prader-Willi syndrome, and at least some cases of autosomal recessive ocular albinism.

We previously reported that endostatin inhibits endothelial and tumor cellular invasion by blocking activation and catalytic activity of matrix metalloproteinase (MMP)-2. Here we have examined the domain of proMMP-2 responsible for the binding of endostatin using surface plasmon resonance. ProMMP-2 and proMMP-2deltaHP lacking the hinge and hemopexin-like (HP) domains bound little to the immobilized endostatin. The active MMP-2 and MMP-2deltaHP, but not the HP domain of MMP-2, bound to endostatin

We have used the reverse transcription-polymerase chain reaction to survey the repertoire of protein tyrosine kinases expressed in cultured normal human melanocytes, a differentiated cell type derived from the neural crest. We identified 25 different tyrosine kinase cDNAs among a total of 608 protein tyrosinase kinase-related cDNAs analyzed. Six encode receptor tyrosine kinases for known ligands, several of which have been implicated in controlling melanocyte proliferation in vitro. Two others e

Type II (tyrosinase-positive) oculocutaneous albinism (OCA2) is an autosomal recessive disorder in which the biosynthesis of melanin pigment is reduced in the skin, hair, and eyes. OCA2, which we have shown results from mutations of the P gene in Caucasians, is the most prevalent type of oculocutaneous albinism in African and African-American patients with OCA. We have identified abnormalities of the P gene in seven unrelated African-American patients with OCA2, including three large deletions,

A 220-bp fragment of PTK7 cDNA was previously cloned from normal human melanocyte RNAs by means of the reverse transcription-polymerase chain reaction [Lee, S.-T., Strunk, K.M., and Spritz, R.A. (1993) Oncogene 8, 3403-3410]. We now report the cloning of the human full-length PTK7 cDNA and its characterization. The 1,070 amino acid PTK7 polypeptide deduced from the cDNA sequence constitutes receptor protein tyrosine kinase (RPTK), but has several unusual residues in some of the highly conserved

Esophageal squamous cell carcinoma (ESCC) is a common subtype of esophageal cancer that is particularly prevalent in East Asian countries. Our previous expression profile analysis showed that the gene encoding protein tyrosine kinase 7 (PTK7) is upregulated in ESCC tissues. Here, we aimed to validate PTK7 as a prognostic factor and a candidate target for molecular treatment of ESCC. Both RT-PCR and Western blot analysis of tissues from ESCC patients revealed that PTK7 was significantly upregulat

Tenascin C (TNC) is an element of the extracellular matrix (ECM) of various tissues, including the skin, and is involved in modulating ECM integrity and cell physiology. Although skin aging is apparently associated with changes in the ECM, little is known about the role of TNC in skin aging. In this study, we found that the <i>Tnc</i> mRNA level was significantly reduced in the skin tissues of aged mice compared with young mice, consistent with reduced TNC protein expression in aged human skin.

Skullcapflavone II is a flavonoid derived from the root of <i>Scutellaria baicalensis</i>, a herbal medicine used for anti-inflammatory and anti-cancer therapies. We analyzed the effect of skullcapflavone II on the expression of matrix metalloproteinase-1 (MMP-1) and integrity of type I collagen in foreskin fibroblasts. Skullcapflavone II did not affect the secretion of type I collagen but reduced the secretion of MMP-1 in a dose- and time-dependent manner. Real-time reverse transcription-PCR an