Parathyroid hormone stimulates protein kinase C but not adenylate cyclase in mouse epidermal keratinocytes. |
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| Authors: | J F Whitfield B R Chakravarthy J P Durkin R J Isaacs H Jouishomme M Sikorska R E Williams R H Rixon |
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| Institution: | Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario. |
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| Abstract: | Intact human parathyroid hormone, hPTH 1-84], and the hPTH 1-34] fragment stimulated membrane-associated protein kinase C (PKC) activity in immortalized (but still differentiation-competent) murine BALB/MK-2 skin keratinocytes. Unexpectedly, the hormone and its fragment did not stimulate adenylate cyclase. The failure of PTH to stimulate adenylate cyclase activity was not due to the lack of a functioning receptor-cyclase coupling mechanism because the cells were stimulated to synthesize cyclic adenosine monophosphate (cyclic AMP) by the beta-adrenergic drug isoproterenol. Thus, skin keratinocytes seem to have an unconventional PTH receptor that is coupled to a PKC-activating mechanism but not to adenylate cyclase. These observations suggest that normal and neoplastic skin keratinocytes respond to the PTH-related peptide that they make and secrete. |
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