Cell Growth & Differentiation, Vol 4, Issue 12 1005-1012, Copyright © 1993 by American Association of Cancer Research
Differential expression of cyclic AMP-dependent protein kinase isozymes in normal human melanocytes and malignant melanomas
SJ Beebe, P Salomonsky, C Holroyd and D Becker
Department of Pediatrics, Eastern Virginia Medical School, Norfolk 23510.
Analysis of cyclic AMP-dependent protein kinase catalytic (C) and
regulatory (R) subunits in normal human melanocytes and malignant melanomas
demonstrated molar excess of regulatory over catalytic subunit in both cell
types. Overall, greater catalytic activity, as a measure of C subunit, and
cyclic AMP binding activity, as a measure of R subunit, were detected in
metastatic compared to primary melanomas compared to normal human
melanocytes. The protein kinase-specific R subunits, expressed in both
melanocytes and malignant melanomas, were identified as RI-alpha and
RII-alpha. Differences were noted for the ratios of RI/RII and RI
holoenzyme/free RI subunit among different melanomas.