ISSN:
1600-0625
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: Capacitive calcium influx is associated with the release of calcium from internal stores and participates in intracellular calcium homeostasis. In keratinocytes, its activation is linked to the stimulation of the phospho-inositide (PI) pathway and seems to be altered in psoriasis. An overnight treatment of isolated HaCaT keratinocytes with phorbol 12-myristate 13-acetate (PMA) selectively downregulated the classical, calcium-dependent protein kinase C (PKC) isoenzyme PKCα in preconfluent cells. This was parallelled by an increased capacitative calcium influx with no effects on the PI pathway. These observations were strengthened in measurements using cyclopiazonic acid which revealed a 47% increase in PMA pretreated as compared with control cells in the calcium influx rate through store-operated calcium channels (SOC-s) following the emptying of the intracellular calcium stores. In confluent as compared with preconfluent cultures PKCε was markedly increased, while other isoenzymes were not affected. In parallel, the kinetics of capacitative calcium influx were altered, showing clear inactivation. PMA pretreatment in these cells had little effect on PKCα but downregulated both PKCβ and PKCε, and did not increase the influx through SOC-s. These observations support the differential regulation of SOC-s by PKC and suggest the involvement of several PKC isoenzymes in human keratinocytes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1034/j.1600-0625.2002.110103.x
