SC-9

Manipulation of phototransductive membrane turnover by crab photoreceptors in vitro: effects of two protein kinase activators, SC-9 and phorbol ester in the presence of a protein phosphatase inhibitor, okadaic acid.[Pubmed:1316437]

J Comp Physiol A. 1992 Feb;170(2):189-99.

1. Retinae of crabs, Leptograpsus variegatus, held on a 12:12 h light-dark cycle were prepared for culture in vitro shortly before light-off. After an hour in darkness to permit the assembly of "night" rhabdoms, retinae were exposed to various combinations of drugs: 1 microM okadaic acid (OKA); 60 microM SC-9; 10 microM phorbol, 12,13-diacetate (PDA). 2. The effects of the specific protein phosphatase inhibitor, OKA, are confirmed as light-dependent. Rhabdom sizes were not compromised by OKA, nor by either of the two protein kinase activators, SC-9 or PDA when each was deployed alone in darkness. 3. In combination with OKA, PDA induced demolition of rhabdoms by abnormal macropinocytosis of microvillar membranes. 4. Combined with OKA, SC-9 induced a transient reduction of rhabdoms, followed by overgrowth to abnormal sizes. Overgrowth was blocked by the transcription inhibitor actinomycin D. 5. Disparate consequences of combining OKA with SC-9 or PDA imply that more than one protein kinase C may be involved.

Effects of activators (SC-9 and OAG) and inhibitors (staurosporine and H-7) of protein kinase C on the proliferation of mouse epidermal melanoblasts in serum-free culture.[Pubmed:7962208]

J Cell Sci. 1994 Jun;107 ( Pt 6):1679-86.

Mouse epidermal melanoblasts preferentially proliferated from disaggregated epidermal cell suspensions derived from newborn mouse skin in a serum-free melanoblast proliferation medium containing dibutyryl adenosine 3':5'-cyclic monophosphate and basic fibroblast growth factor. After 12 days, almost all of the keratinocytes died and pure cultures of melanoblasts (approximately 80%) and melanocytes (approximately 20%) could be obtained. No further proliferation of melanoblasts was observed in the melanoblast proliferation medium. In order to clarify the role of protein kinase C, which is important for the regulation of cellular proliferation, activators or inhibitors of protein kinase C were added to the culture of the quiescent melanoblasts at 12 days. The proliferation of melanoblasts was induced by an activator of protein kinase C, N-(6-phenylhexyl)-5-chloro-1-naphthalene-sulfonamide or 1-oleoyl-2-acetyl-glycerol. It was also induced by an inhibitor of protein kinase C, staurosporine or 1-(5-isoquinolinesulfonyl)-2-methyl-piperazine. However, the melanoblasts failed to proliferate in the melanoblast proliferation medium supplemented with both the activator and the inhibitor. These results suggest that the proliferation of mouse epidermal melanoblasts in culture is regulated by activating or inhibiting the activity of protein kinase C.

N-(6-phenylhexyl)-5-chloro-1-naphthalenesulfonamide, a novel activator of protein kinase C.[Pubmed:3756133]

Biochemistry. 1986 Jul 29;25(15):4179-84.

Naphthalenesulfonamide derivatives were used to study the mechanism of regulation of Ca2+-dependent smooth muscle myosin light chain phosphorylation catalyzed by Ca2+-activated, phospholipid-dependent protein kinase (protein kinase C) and myosin light chain kinase. Derivatives such as N-(6-phenylhexyl)-5-chloro-1-naphthalenesulfonamide (SC-9), with a hydrophobic residue at the end of a hydrocarbon chain, stimulated Ca2+-activated, phospholipid-dependent myosin light chain phosphorylation in a Ca2+-dependent fashion. There was no significant effect of these compounds on Ca2+-calmodulin (CaM) dependent myosin light chain phosphorylation. On the other hand, derivatives with the guanidino or amino residue at the same position had an inhibitory effect on both Ca2+-phospholipid- and Ca2+-CaM-dependent myosin light chain phosphorylation. These observations suggest that activation of Ca2+-activated, phospholipid-dependent myosin light chain phosphorylation by naphthalenesulfonamide derivatives depends on the chemical structure at the end of hydrocarbon chain of each compound. SC-9 was similar to phosphatidylserine with regard to activation, and the apparent Km values for Ca2+ of the enzyme with this compound and phosphatidylserine were 40 microM and 80 microM, respectively. Kinetic analysis indicated that 12-O-tetradecanoylphorbol 13-acetate increased the affinity of the enzyme with SC-9 for calcium ion. However, kinetic constants revealed that the Km value of protein kinase C activated by SC-9 for substrate myosin light chain was 5.8 microM, that is, about 10 times lower than that of the enzyme with phosphatidylserine, and that the Vmax value with SC-9 was 0.13 nmol X min-1, that is, 3-fold smaller than that seen with phosphatidylserine.(ABSTRACT TRUNCATED AT 250 WORDS)

N-(6-phenylhexyl)-5-chloro-1-naphthalenesulfonamide is one of a new class of activators for Ca2+-activated, phospholipid-dependent protein kinase.[Pubmed:3778949]

Biochim Biophys Acta. 1986 Nov 28;889(2):236-9.

N-(6-Phenylhexyl)-5-chloro-1-naphthalenesulfonamide (SC-9) activated Ca2+-activated, phospholipid-dependent protein kinase (protein kinase C). SC-9 acted as a substitute for phosphatidylserine, which is one of the endogenous factors in activating protein kinase C. SC-9 was also effective in regulating the physiological functions at the whole-cell level. For example, SC-9 stimulated hexose transport activity in mouse fibroblasts, a protein kinase C-regulated cellular function. Thus, SC-9 may be useful to study the molecular basis of the regulation of protein kinase C activity, and the biological significance of this enzyme.