Abstract
We utilized an expression screen to identify two novel Ca(2+)/calmodulin (CaM)-regulated protein kinases in Aspergillus nidulans. The two kinases, CMKB and CMKC, possess high sequence identity with mammalian CaM kinases (CaMKs) I/IV and CaMKKalpha/beta, respectively. In vitro CMKC phosphorylates and increases the activity of CMKB, indicating they are biochemical homologues of CaMKKalpha/beta and CaMKI/IV. The disruption of CMKB is lethal; however, when protein expression is postponed, the spores germinate with delayed kinetics. The observed lag corresponds to a delay in the G(1)-phase activation of the cyclin-dependent kinase NIMX(cdc2). Disruption of cmkC is not lethal, but spores lacking CMKC also germinate with delayed kinetics and a lag in the activation of NIMX(cdc2). Analysis of DeltacmkC suggests a role for CMKC in regulating the first and subsequent nuclear division cycles. We conclude that both CMKB and CMKC are required for the proper temporal activation of NIMX(cdc2) as spores enter the cell cycle from quiescence and suggest that this relationship exists during the G(1)/S transition of subsequent cell divisions.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
