Research & Teaching Faculty

Default Header Image

Cdc4p, a contractile ring protein essential for cytokinesis in Schizosaccharomyces pombe, interacts with a phosphatidylinositol 4-kinase

TitleCdc4p, a contractile ring protein essential for cytokinesis in Schizosaccharomyces pombe, interacts with a phosphatidylinositol 4-kinase
Publication TypeJournal Article
Year of Publication2001
AuthorsDesautels, M, Haese, JPDen, Slupsky, CM, McIntosh, LP, Hemmingsen, SM
JournalJournal of Biological Chemistry
Volume276
Pagination5932-5942
Date PublishedFeb
Type of ArticleArticle
ISBN Number0021-9258
KeywordsACTOMYOSIN RING, BINDING, CELL-DIVISION CYCLE, F-ACTIN, FISSION YEAST, GENE, IDENTIFICATION, LIGHT-CHAIN, LOCALIZATION, MYOSIN HEAVY-CHAIN
Abstract

The proposed function of Cdc4p, an essential contractile ring protein in Schizosaccharomyces pombe, is that of a myosin essential light chain. However, five conditionally lethal cdc4 alleles exhibit complementation in diploids. Such interallelic complementation is not readily explained if the sole function of Cde4p is that of a myosin essential light chain. Complementation of cdc4 alleles could occur only if different mutant forms can assemble into an active oligomeric complex or if Cdc4p has more than one essential function. To search for other proteins that may interact with Cdc4p, we performed a two-hybrid screen and identified two such candidates: one similar to Saccharomyces cerevisiae Vps27p and the other a putative phosphatidylinositol (PI) 4-kinase. finding of Cdc4p to the latter and to myosin heavy chain (Myo2p) was confirmed by immunosorbent assays. Deletion studies demonstrated interaction between the Cdc4p C-terminal domain and the PI 4-kinase C-terminal domain. Furthermore, interaction was abolished by the Cdc4p C-terminal domain point mutation, Gly(107) to Ser. This allele also causes failure of cytokinesis. Ectopic expression of the PI 4-kinase C-terminal domain caused cytokinesis defects that were most extreme in cells carrying the G107S allele. We suggest that Cdc4p plays multiple roles in cytokinesis and that interaction with a PI I-kinase may be important for contractile ring assembly and/or function.

URL<Go to ISI>://000167115100071