Display Settings:

Format

Send to:

Choose Destination
We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Proc Natl Acad Sci U S A. 1998 Dec 8;95(25):14781-6.

Negative regulation of mitosis in fission yeast by the shk1 interacting protein skb1 and its human homolog, Skb1Hs.

Author information

  • 1Department of Molecular Genetics, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.

Abstract

We previously provided evidence that the protein encoded by the highly conserved skb1 gene is a putative regulator of Shk1, a p21(Cdc42/Rac)-activated kinase (PAK) homolog in the fission yeast Schizosaccharomyces pombe. skb1 null mutants are viable and competent for mating but less elongate than wild-type S. pombe cells, whereas cells that overexpress skb1 are hyperelongated. These phenotypes suggest a possible role for Skb1 as a mitotic inhibitor. Here we show genetic interactions of both skb1 and shk1 with genes encoding key mitotic regulators in S. pombe. Our results indicate that Skb1 negatively regulates mitosis by a mechanism that is independent of the Cdc2-activating phosphatase Cdc25 but that is at least partially dependent on Shk1 and the Cdc2 inhibitory kinase Wee1. We provide biochemical evidence for association of Skb1 and Shk1 with Cdc2 in S. pombe, suggesting that Skb1 and Shk1 inhibit mitosis through interaction with the Cdc2 complex, rather than by an indirect mechanism. These results provide evidence of a previously undescribed role for PAK-related protein kinases as mitotic inhibitors. We also describe the cloning of a human homolog of skb1, SKB1Hs, and show that it can functionally replace skb1 in S. pombe. Thus, the molecular functions of Skb1-related proteins have likely been substantially conserved through evolution.

PMID:
9843966
[PubMed - indexed for MEDLINE]
PMCID:
PMC24526
Free PMC Article

Images from this publication.See all images (5)Free text

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk