The intracellular signal pathways that mediate pigmentation in human skin are unknown. We now report that a diacylglycerol (DAG) analogue 1-oleoyl-2-acetyl-glycerol (OAG) 25-100 microns strikingly increased the melanin content of cultured human melanocytes in a dose dependent manner without altering growth rate. The pigment increase occurred within 24 h, was accompanied by increased incorporati...

A protein kinase that is activated by calcium and cis-unsaturated fatty acids has been characterized from oat (Avena sativa L.) root plasma membranes. The kinase phosphorylates a synthetic peptide with a motif (-R-T-L-S-) that can be phosphorylated by both protein kinase C (PKC) and calcium-dependent protein kinase (CDPK)-type kinases. Calphostin C and chelerythrine, two PKC inhibitors, complet...

The protein-tyrosine kinase (PTK) v-Fps induces protein kinase C (PKC)-dependent expression of the transformation-related 9E3 gene in chicken embryo fibroblasts (Spangler, R., Joseph, C., Qureshi, S.A., Berg, K., and Foster, D.A. (1989) Proc. Natl. Acad. Sci. U.S.A. 86, 7017-7021). We present evidence here that a GTP-binding protein (G-protein) is a component of this PKC-dependent signaling pat...

Epidermal homeostasis relies on the progenitors to continuously proliferate or initiate differentiation. The molecular mechanisms underlying earliest events of differentiation initiation remain incompletely understood. Here we show that kinase activity CDK9, in association with Super Elongation Complex (SEC), plays a crucial role process. Progenitor-state keratinocytes are associated inactive C...

Type-2 calcium-dependent potassium (KCa) channels from mammalian brain, reconstituted into planar phospholipid bilayers, are modulated by ATP or ATP analogs via an endogenous protein kinase activity intimately associated with the channel (Chung et al., 1991). We show here that the endogenous protein kinase activity is protein kinase C (PKC)-like because (1) modulation by ATP can be mimicked by ...

Regulated expression of Na+ channels is indispensable to physiological events, whereas dysregulated expression of otherwise silent or even normal Na+ channel isoforms causes Na+ channelopathies; however, the regulatory mechanisms remain unknown. In quiescent cultured bovine adrenal chromaffin cells, constitutive phosphorylation/activation of extracellular signal-regulated kinase-1 (ERK1) and ER...

Phorbol ester-sensitive EL4 murine thymoma cells respond to phorbol 12-myristate 13-acetate with activation of ERK mitogen-activated protein kinases, synthesis of interleukin-2, and death, whereas phorbol ester-resistant variants of this cell line do not exhibit these responses. Additional aspects of the resistant phenotype were examined, using a newly-established resistant cell line. Phorbol e...

We have shown previously that activation of protein kinase C(PKC ) is required for angiotensin II (Ang II)–induced migration of vascular smooth muscle cells (VSMCs). Here, we have hypothesized that PKC phosphorylation at Tyr plays a critical role in VSMC hypertrophy induced by Ang II. Immunoblotting was used to monitor PKC phosphorylation at Tyr, and cell size and protein measurements were used...