p34cdc2 is located in both nucleus and cytoplasm; part is centrosomally associated at G2/M and enters vesicles at anaphase.

Abstract

The cdc2+ gene product p34cdc2 is located immunocytochemically in both the nucleus and cytoplasm of human cells. It is uniformly distributed throughout the cytoplasm and is irregularly distributed in the nucleus. Part of p34cdc2 is associated with the centrosome and centrosomal staining increases late in the cell cycle and at the onset of mitosis. This distribution is corroborated by cell fractionation which also indicates that slower migrating forms of p34cdc2 are found in isolated centrosomes and in Triton-insoluble fractions. We propose that one role of the p34Cdc2 protein kinase is to modify the centrosome bringing about formation of the mitotic spindle. At anaphase p34cdc2 becomes associated with vesicles in the middle of the cell between the reforming nuclei. A similar location is found for pl3SUCl and we suggest that the vesicular localization plays a role in p34cdc2 kinase inactivation at the end of mitosis.

Getting in and out of mitosis with Polo-like kinase-1

“…Interestingly, more and more evidence is accumulating that the (maturing) centrosome could play a key role in the initial activation of Cyclin B-Cdk1. Immunocytochemically, a fraction of Cdk1 that is bound to Cyclin B was shown to localize to centrosomes during interphase (Bailly et al, 1989(Bailly et al, , 1992. Initially, this localization pattern was suggested to regulate centrosome functioning.…”

cut11+: A Gene Required for Cell Cycle-dependent Spindle Pole Body Anchoring in the Nuclear Envelope and Bipolar Spindle Formation inSchizosaccharomyces pombe

“…The principal cell cycle regulatory enzyme in fission yeast is the cyclindependent kinase cdc2 ϩ , and its activity is required for entry into mitosis (Bailly et al, 1989;Alfa et al, 1990;reviewed in Forsburg and Nurse, 1991). There are, however, no putative modification sites for this enzyme in the Cut11p sequence.…”

“…The spindle is constructed from microtubules (MT) 1 whose polymerization is nucleated by the centrosome (reviewed in Kellogg et al, 1994), which is known in fungi as the spindle pole body (SPB) (reviewed in Snyder, 1994). Although these two organelles are structurally distinct, genetic and biochemical approaches have identified several common components of centrosomes and SPBs, including ␥-tubulin (reviewed in Kellogg et al, 1994), CDC31/centrin (reviewed in Schiebel and Bornes, 1995), and p34 cdc2 (Bailly et al, 1989;Raibowol et al, 1989). Thus, analyses of SPBs have been informative about centrosomes in general.…”

Immunolocalization of the cellular src protein in interphase and mitotic NIH c-src overexpresser cells.

“…This observation indicates that the preferential association of pp60 .... with the material surrounding the centrioles is lost following the breakdown of the nuclear envelope and the beginning of spindle formation. The p34 acz protein kinase, a major cell cycle regulatory kinase (for reviews see Dunphy et al, 1988;Murray, 1988;lee and Nurse, 1988;Gautier et al, 1988) has been shown to be a nuclear and cytoplasmic protein with a cell cycle-dependent accumulation at the centrosome (Akhurst et al, 1979;Bailly et al, 1989), although a strictly nuclear localization has been reported by others (Riabowol et al, 1989). This protein is capable in vitro of phosphorylating pp60 .... at the same sites as those phosphorylated in vivo during fibroblast mitosis (Chakalaparampil and Shalloway, 1988;Shenoy et al, 1989;Morgan et al, 1989).…”