lnositol
lipids
in cell signalling
by
Robin F. Irvine FINCH EA, TUNER FJ, GOLDIN SM: Calcium as a Co-ag onist of Inositol 1,4,5trisphosphateinduced Calcium Release. Science WI, 252443-446. Using an elegant rapid superfusion technique to measure Ca2+ release, the authors show that IP+irnulated Ca2+ release is critically dependent on the free Ca2+ level: below or above the limits of a bell shaped curve, there is little release. BEZPROZVANN~ I, WATRASJ, EHRIXH BE: Bell-shaped
distributed randomly in young cells, but in older cells it assembles a ring-like structure on the inner membrane at the future cell division site before visible pinching, but after chromosome segregation.
by Takeharu Nishimoto, Satoru Uzawa and Robert Schlegel
Mitotic
checkpoints
BISCHOFFFR, PONSTINGLH: Catalysis of Guanine Nucleotide Exchange on Ran by the Mitotic Regulator RCCl. Nature 1991, 3548082.
Calcium-response Curves of Ins( 1,4,5)P3 and Calcium-gated Channels from Endoplasmic Reticulum of Cerebellum. Nature 1991, 35 1:751-754.
This outstanding paper shows that RCCl can catalyze the exchange of guanine nucleotides on Ran and/or TC4.
This study arrives independently at the same conclusions as Finch et al although,in this case,single-channel activity is used as an assay, employing membrane vesicles fused with planar lipid bilayers.
OSMANI AH, MCGUIRE SL, OSMANI SA Parallel Activation of the NIMA and p34cdc2 Cell Cycle-regulated Protein Kinases is Required to Initiate Mitosis in R
LOXHOFF A, CIAPHAMDE: Iuositol 1,3,4,5-tetraldsphosphate Activates an Endothelial Ca*+ Channel. Nature
This outstanding paper shows that the protein kinases NIMA and p34do must both be activated for cells to enter mitosis.
1992, 355:356-358. IF’4 is shown to activate an endothelial Ca2+ channel. Although this speaks for itself, it does not reveal what a formidable piece of patch-clamping was required to detect and characterize a single channel with a conductance of 2.5 pS. It is postulated that this might be the elusive second-messenger-operated Ca2+ channel.
nidulans. Cell 1991, 61283-291.
Modification of cell proliferation with inhibitors by Arthur B. Pardee and
Khandan
Keyomarsi
CRISSMANHA, GADBOIS DM, TOBEY RA, BRADBURV EM: Transformed Mammalian Cells are Deficient in Cell cycle
regulation
Austin Newton
in bacteria
and Noriko
Kinase-mediated Control of Progression Through the Gl Phase of the Cell Cycle. Pm Nat1Acud Sci CTS
by
Ohta
A 1991, 88:758&7584.
KUEMPELPL, HENSON JM, DIRCK~ L, TECKLENBURGM, ILM DF: diJ a e&independent Recombination Site
iu the Terminus Region of the Chromosome
of Es-
chericbia coli. N Biol 1991, 3~799811. This work identilied the chromosome terminus sequence, d$ and showed that mutations in difresulted in a lilamentous phenotype that was suppressed by defects in homologous recombination. By analogy to the cer site in ColEI DNA with which dfis homologous, it is proposed that dgacts In cis as a site for the resolution of dimeric chromosomes, BI E, LUTKENHAUSJ: FtsZ Riug Structure Associated with Division in Eschericbia coli. Nature 1991, 354:161-164. The use of immuno-gold electron microscopy has permitted the hrst spatial localization of the F&Z protein in E. coli cells. This predominantly cytoplasmic protein is
Erratum: minute”
228
VASILIEV J: Actin filaments on the move. in paragraph 5, line 6 should be replaced
The role of staurosporine, a general protein kinase inhibitor, in the proliferation of a series of non-transformed and transformed cultured rodent and human cells is analyzed. Staurosporine was ineffective in Gl progression and initiation of DNA replication in transformed cultures, suggesting that the consequence of neoplastic transformation is a loss of kinase-mediated regulation of proliferation. GUYIZER M, MURRAYAW, KIRXHNER Mw, Cyclin is by the Ubiquitin Pathway. Nature 1991, 349:132-138.
Degraded
A very significant study on cyclin degradation by the ubiquitin pathway. The results presented suggest that the Mphase-promoting factor, MPF, regulates the conjugation of ubiquitin to cyclin, leading to the rapid destruction of cyclin by the constitutively active ubiquitin-dependent proteolytic system.
Curr Biol 1992, 260-61. “10 pm wide” in paragraph 4, line 21 and by “1 pm wide” and “4.5 pm per minute”, respectively.
“45 pm
per
0 1992 Current Biology