Biology..

G0 is an arrest phase, there are no divisions in this stage, however cells carry out their normal function and most cells are found at this stage, now if you inhibit a kinase (and I don't know which type you mean as there are several) then in all likelihood it will not affect the cell cycle progression but it might have a reversible arrest on some of the functions or products that these cells are responsible for, for instance fibroblasts.

I am not sure I understand your question correctly and I apologize if I am missing something as it has been ages since I left biology behind..

so Allah swt knows best

thanks for answering sister , may Allah reward you .

in all likelihood it will not affect the cell cycle progression

but if kinase is not working how will the cell enter the M-phase ? so how the cell cycle progression will continue ?

format_quote Originally Posted by *Yasmin*

thanks for answering sister , may Allah reward you .


but if kinase is not working how will the cell enter the M-phase ? so how the cell cycle progression will continue ?

a kinase only makes an enzyme active, and an enzyme is really nothing more than a catalyst as in accelerating a chemical reaction but not responsible for it taking place..
again pls. understand I am just speculating/theorizing ..perhaps your text book will say differently.

kinase is enzyme that makes phosphorylation to M-cdk and M-cdk affect systems in the cell that make the division .
this is what i learned .

this was a question from a previous exam i'm solving . but don't have the answers for it.i wasn't sure from the answer this is why i asked .
anyway ^_^

thanks for your effort answering me ,i appreciate you and your time ^^
salam

I am confused by your queries, are you asking about M-CDK inhibition? or the CDK dependent catalysts (kinases)? CDK inhibition itself is used or at least in trial phases for cancer therapy in fact most of the antineoplastics you'll encounter work on some phase or another in the cell cycle. The catalysts themselves though speed a reaction are not responsible for it taking place, they merely accelerate it. If you inhibit M-CDK completely you'll inhibit mitosis!

anyhow good luck on your research insha'Allah, once you find out the correct answer pls do share

format_quote Originally Posted by Grofica

Skye you are entirely too smart.... the only part i understood was when you said good luck.

Jazaki Allah khyran.. I really don't think so, and I fear I didn't answer her question to satisfaction.. nonetheless I am certain that she will find the right answer..

format_quote Originally Posted by Grofica

Skye you are entirely too smart.... the only part i understood was when you said good luck.

Mashallah

format_quote Originally Posted by Gossamer skye

I am confused by your queries, are you asking about M-CDK inhibition? or the CDK dependent catalysts (kinases)? CDK inhibition itself is used or at least in trial phases for cancer therapy in fact most of the antineoplastics you'll encounter work on some phase or another in the cell cycle. The catalysts themselves though speed a reaction are not responsible for it taking place, they merely accelerate it. If you inhibit M-CDK completely you'll inhibit mitosis!

anyhow good luck on your research insha'Allah, once you find out the correct answer pls do share

hmmm i see ..
i'm asking about cdk dependent kinase tho'..
my question now : if there is no kinases in the cell will the division cycle occur ? you said it just speed the reaction ?

sorry for my questions but i have a final exam

really thank you sister , you are great

i'll try to find the correct answer in sha' Allah

format_quote Originally Posted by *Yasmin*

i have a question .. hope you can answer
through the cell division cycle .M-cdk is going throw phosphorylation and dephosphorylation.. if a mutation happened and affected the activating kinase .. what will happen to the cells?

will they stop in G0 of the cell division cycle? or what ?

If i understand right you're talking about the control of the cell cycle. Right?

Let me explain from the begining.

Cell grows during the G1 phase and the genome replicates during the S phase. During the G2 phase, cells continue to grow and prepare for cells division. During M phase, mitosis occurs. Cytokinesis (C) is the phase when the cytoplasm divides, creating two daughter cells.











^3 princicple checkpoints control the cell cycle in eukaryotes.

• The G1 checkpoint makes the key decision as to whether the cell should divide, delay division or enter a resting stage.
• The G2 checkpoint assess the success of DNA replication and trigers the start of the mitosis (M) phase. If this checkpoint is passes the cell initiates the begining of mitosis.
• The accuracy of mitosis is assessed at the M checkpoint. This checkpoint occurs during metaphase, trigers the exit from mitosis and cytokinesis and the beigining of G1.

At the G2 checkpoint, cyclin-dependant kinases (CDKs) phosphorylate histones and protein that carry the cycle past the checkpoint into mitosis. During G2, the cell gradually accumulates G2 cyclin (also called mitotic cyclin).

The cyclin binds to Cdk to form a complex called MPF (mitosis pomoting factor). When the level of MPF exceeds the threshold necessary to trigger mitosis, the G2 phase ends and mitosis begins. MPF also activates proteins that destroy cyclin.

As mitosis proceeds to the end of metaphase, Cdk levels stay relatively constant but G2 cyclin is degraded, causing less MPF to be availible and initiating the events that end mitosis.

After mitosis, the gradual accumulation of new cyclin starts the next turn of the cell cycle.

The G1 checkpoint is thought to be regulated in a similar fashion. The level of G1 cyclin increases and associates with Cdk. Eventually, a threshold ratio that trigers the next round of DNA replication is reached. The cyclin is degraded and the cycle begins again.

Coming back to your question now. What if there are no Cdk?

Cdk plays a big part at G2 and G1 checkpoint as explained above. Whatever these checkpoints check (see image) won't be regulated anymore.

In normal circumstances the DNA is frequently damaged prior to mitosis, and to prevent transmission of this damage to daughter cells, the cell cycle is arrested via inactivation of the G2 cyclin during G2 checkpoint (via phosphorylation with other protein kinases). Loss of Cdk will cause a marked deficiency in the M phase arrest.

The G 1 checkpoint is where eukaryotes typically arrest the cell cycle if environmental conditions make cell division impossible or if the cell passes into G0 for an extended period. Again this won't happen if there are no Cdk.

Slightly long but i hope this helps. Insh'Allah.

^ jazake Allahu khayran sister...