The phrase "activities of atm" is not correct in standard written English due to the lack of clarity and context.
It could be used when discussing the functions or operations related to an Automated Teller Machine (ATM), but it needs to be more specific.
Example: "The activities of the ATM include cash withdrawals, balance inquiries, and fund transfers."
Alternatives: "functions of the ATM" or "operations of the ATM".
Each of the above-mentioned activities of ATM, namely, DNA repair and p53 activation, could contribute independently to tumor suppression.
We next determined the effect of S9 on the activities of ATM, ATR and DNA-PK by measuring the level of phosphorylated H2AX (γH2AX).
Besides, taking into account that DDR involves not only gene expression changes, but also posttranslational modifications, mainly due to the kinase activities of ATM and ATR, a profound evaluation of this response should be performed.
For these studies, MCF-7 cells incubated in the presence or absence of NSC23766 were exposed to IR and then examined for the activities of ATM, ATR, Chk1, and Chk2 kinases.
Despite these normal activities of Atm, Nbs1 and Brca1, these cells exhibit a defective S-phase checkpoint, radiosensitivity, and increased chromosomal breakage after IR similar to that seen in cells lacking Atm.
Specifically, a low activity of ATM (ATM-P = 1) is required for inactivation of the ATM phosphatase protein phosphatase 2 A (PP2A) [ 24] (interaction 22).
Once PP2A is inactivated, DSBs can induce high activity of ATM (ATM-P = 2), which is now able to phosphorylate further substrates [ 25] (interaction 23).
DNA damage induced by drugs, such as etoposide, also results in increased AMPK activity, via activation of ATM, as a mechanism to fulfill the energetic requirements of the DNA repair process.
Although not absolutely required for ATM activation, the MRN nuclease complex may help reach the threshold activity of ATM necessary for optimal genome maintenance and prevention of cancer.
As shown in Fig. 4A, the activity of ATM, a kinase that is activated by DNA damage signals and phosphorylates a series of downstream targets such as CHK2, was lower in the cells with silencing of Cav-1 than that in the control cells following IR, as demonstrated by decreased levels of the phospho-ATM (Ser1981) and phospho-CHK2 (Thr68).
These observations suggest that the activity of ATM is required to cause nickase-induced instability in the absence of ATR.
