Premium
A CALCIUM‐DEPENDENT PROTEIN KINASE FUNCTIONS IN WOUND HEALING IN VENTRICARIA VENTRICOSA (CHLOROPHYTA)
Author(s) -
Sugiyama Kohichi,
Mori Izumi C.,
Takahashi Koji,
Muto Shoshi,
ShihiraIshikawa Ikuko
Publication year - 2000
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1046/j.1529-8817.2000.00050.x
Subject(s) - biology , multinucleate , cytoplasm , kinase , protein kinase a , calmodulin , microbiology and biotechnology , immunoprecipitation , actin , wound healing , biochemistry , enzyme , immunology , gene
The cytoplasm around a wound made in the multinucleate unicellular green alga Ventricaria ventricosa ( J. Agardh) Olsen et West formed an aggregation‐ring surrounding the wound immediately after injury. A contraction of the ring then brought about wound healing in culture medium containing Ca 2 + . Involvement of a calcium‐dependent protein kinase (CDPK) as a regulator of wound healing was examined using an anti‐ Dunaliella tertiolecta CDPK antibody. A 52‐kDa protein cross‐reacting with the antibody was detected by Western blotting. Protein kinases of 60 kDa and 52 kDa, which were markedly activated by Ca 2 + , and a 40‐kDa Ca 2 + ‐independent protein kinase were detected by an in‐gel protein kinase assay using myelin basic protein as the substrate. A 52‐kDa band with Ca 2 + ‐dependent protein kinase activity was immunoprecipitated from the cytoplasmic extract, indicating that these 52‐kDa proteins are identical and possess CDPK activity. Microscopic observation showed that the contraction of the aggregation ring was suppressed by application of the anti‐CDPK to the culture medium. A protein kinase inhibitor, K‐252a, and the calmodulin inhibitors, calmidazolium and compound 48 / 80, which inhibit CDPK activity, also suppressed the contraction of the aggregation‐ring. Immunofluorescence microscopy showed a similar distribution of 52‐kDa CDPK to the distribution of f‐actin, which was randomly distributed in an intact cell and formed a bundle during wound healing. Further, f‐actin was not recruited after injury in the presence of the antibody to CDPK. These results suggest that the 52‐kDa CDPK functions as a Ca 2 + receptor in wound healing and simultaneously participates in the organization and contraction of f‐actin to heal the wound.