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Updated: Jul 15, 2026

A Photodynamic Approach to Study Function of Intracellular Vesicle Rupture
Published on: March 17, 2023
Golgi complex disassembly caused by light-activated calphostin C involves MAPK and PKA
J A Morgado-Díaz1, G Montesano, S De Souza Fernandes
1Grupo de Biologia Estrutural, Divisão de Biologia Celular, Centro de Pesquisas, Instituto Nacional de Câncer, Rio de Janeiro, RJ 20231-050, Brazil. jmorgado@inca.gov.br
Abstract:
We examined the participation of MAPK and PKA in the Golgi complex disassembly caused by light-activated Calphostin C in HT-29 cells. When these cells were incubated with Calphostin C, fragmentation and dispersal of the Golgi complex was observed as assessed by immunofluorescence microscopy. Electron microscopy analysis showed that clusters of vesicles and large tubule-vesicular membrane structures, resembling the Golgi remnants present in mitotic cells, substituted the Golgi stacks. In addition, Calphostin C treatment caused inhibition of the endocytic route. We confirmed that the Golgi disassembly was not due to PKC inhibition, and suggested, based on the use of specific inhibitors, that other kinases are involved. It was shown that pretreatment with PD98059 and H-89, both inhibitors of MAPK and PKA, respectively, prior to incubation with Calphostin C, caused blockade of the Golgi disassembly, as well as the inhibition of the endocytic pathway caused by this drug. This finding supports the existence of a novel mechanism by which MAPK and PKA may regulate the Golgi breakdown caused by Calphostin C in HT-29 cells.
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