title: Calcium-dependent regulator protein: localization in mitotic apparatus of eukaryotic cells.
abstract: Calcium-dependent regulator protein is a low molecular weight (17,000), thermostable, calcium binding protein which is structurally homologous to skeletal muscle troponin C. This protein is present in all nonmuscle cells and has been shown to decorate stress fibers in interphase cells by indirect immunofluorescence. Using this procedure we have investigated the distribution of the protein during mitosis of eukaryotic cells. As the cells enter prophase, the distinct cytoplasmic localization disappears commensurate with the dissolution of the cytoskeleton. The regulator protein seems to be randomly distributed throughout the prophase cell, including the region around the condensed chromosomes. However, at prometaphase, it is localized in association with the half-spindles of the mitotic apparatus. Through metaphase and most of anaphase, the protein remains localized between the chromosomes and the poles of the spindle. During late anaphase the protein is also found in the interzone region but rapidly condenses into two small regions, one on each side of the midbody that separates the daughter cells. The regulator protein is not localized in the cleavage furrow during telophase, whereas actin is demonstrable in this region. Indeed, placement of the protein during mitosis is distinct from both that of actin and that of tubulin. The localization of calcium-dependent regulator protein during mitosis suggests that it may mediate the calcium effects on the mitotic apparatus and thus play a role in chromosome movement.
mesh_terms: D000199:Actins / Q000378:metabolism; D000705:Anaphase; D002118:Calcium / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D007399:Interphase; D008677:Metaphase; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis; D009940:Organoids / Q000378:metabolism*; D011418:Prophase; D013692:Telophase
chemical_list: D000199:Actins; D002352:Carrier Proteins; D002118:Calcium
references.citation: J Cell Biol. 1977 Sep;74(3):794-815
references.pmid: 71303
references.citation: J Cell Biol. 1976 Dec;71(3):848-75
references.pmid: 62755
references.citation: J Biol Chem. 1978 Jan 25;253(2):343-6
references.pmid: 201628
references.citation: J Biol Chem. 1977 Dec 10;252(23):8415-22
references.pmid: 200611
references.citation: J Biol Chem. 1977 Apr 10;252(7):2437-40
references.pmid: 191460
references.citation: Proc Natl Acad Sci U S A. 1977 Apr;74(4):1610-3
references.pmid: 140377
references.citation: Biochem Biophys Res Commun. 1977 Oct 24;78(4):1263-72
references.pmid: 144501
references.citation: J Cell Biol. 1977 Mar;72(3):552-67
references.pmid: 320217
references.citation: J Cell Biol. 1975 Dec;67(3):789-800
references.pmid: 1238405
references.citation: J Biol Chem. 1971 May 10;246(9):2859-69
references.pmid: 4324340
references.citation: Biochim Biophys Acta. 1974 Apr 25;341(2):402-11
references.pmid: 4365089
references.citation: J Biol Chem. 1973 Sep 10;248(17):5950-5
references.pmid: 4353626
references.citation: Biochem Biophys Res Commun. 1970 Feb 6;38(3):533-8
references.pmid: 4315350
references.citation: Exp Cell Res. 1973 Sep;81(1):87-94
references.pmid: 4271272
references.citation: Exp Cell Res. 1972 Feb;70(2):325-32
references.pmid: 4258131
references.citation: Proc Natl Acad Sci U S A. 1974 Jun;71(6):2268-72
references.pmid: 4210210
references.citation: Proc Natl Acad Sci U S A. 1973 Jun;70(6):1688-92
references.pmid: 4578441
references.citation: Exp Cell Res. 1974 May;86(1):161-4
references.pmid: 4598461
references.citation: J Biol Chem. 1976 Aug 10;251(15):4495-500
references.pmid: 181374
references.citation: Adv Cyclic Nucleotide Res. 1975;5:179-94
references.pmid: 165665
references.citation: Biochem J. 1975 Jan;146(1):109-20
references.pmid: 167710
references.citation: Biochem Biophys Res Commun. 1975 Aug 4;65(3):975-82
references.pmid: 168896
references.citation: Proc Natl Acad Sci U S A. 1975 Dec;72(12):4981-5
references.pmid: 174086
references.citation: Science. 1975 Mar 14;187(4180):948-50
references.pmid: 1096300
references.citation: Proc Natl Acad Sci U S A. 1975 Jun;72(6):2451-5
references.pmid: 1094471
references.citation: Exp Cell Res. 1975 Sep;94(2):409-25
references.pmid: 1238267
references.citation: J Cell Biol. 1975 Dec;67(3):501-17
references.pmid: 1238403