Abstract.
In previous studies, we showed that lacrimal gland acini express three isoforms of protein kinase C (PKC): PKCα,-δ, and -ε. In the present study, we report the identification of two other PKC isoforms, namely PKCμ and -ι/λ. Using immunofluorescence techniques, we showed that these isoforms are differentially located. PKCα and -μ showed the most prominent membrane localization, whereas PKCδ, -ε and -ι/λ were mainly cytosolic. Using cell fractionation and western blotting techniques, we showed that the phorbol ester, phorbol 12, 13-dibutyrate (PdBu, 10−6 m), translocated all PKC isoforms, except PKCι/λ, from the soluble fraction into the particulate fraction. The effect was maximum at 5 min and persisted at 10 min. PKCε was the most responsive to PdBu reaching almost maximal translocation at a PdBu concentration as low as 10−9 m. The cholinergic agonist, carbachol (10−5 and 10−3 m), induced translocation which was transient for PKCδ, and -μ, but persisted for 10 min for PKCε. Carbachol did not translocate PKCα and, like PdBu, did not translocate PKCι/λ. We concluded that lacrimal gland PKC isoforms are differentially localized and that they translocate differentially in response to phorbol esters and cholinergic agonists.
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Received: 25 June 1996/Revised: 24 December 1996
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Zoukhri, D., Hodges, R., Willert, S. et al. Immunolocalization of Lacrimal Gland PKC Isoforms. Effect of Phorbol Esters and Cholinergic Agonists on Their Cellular Distribution . J. Membrane Biol. 157 , 169 –175 (1997). https://doi.org/10.1007/s002329900226
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DOI: https://doi.org/10.1007/s002329900226