Cellular survival is a critical process in normal mammalian development, with approximately half of all neurons and over 99.9% of cells in the human body dying through apoptosis. This process is highly regulated and can be suppressed by extracellular stimuli. The discovery of nerve growth factor (NGF) in the 1950s showed that peptide trophic factors promote cell survival. Recent studies have linked the phosphatidylinositide 3'-OH kinase (PI3K)/c-Akt kinase cascade to survival. This cascade has several targets, including BAD, caspase 9, forkhead family transcription factors, and the NF-κB regulator IKK, which are involved in cell survival. PI3K activity is essential for survival downstream of extracellular stimuli. It is activated by various receptors, including those with intrinsic tyrosine kinase activity, indirectly coupled to tyrosine kinases, or coupled to G protein-coupled receptors. PI3K generates 3'-phosphorylated phosphoinositides, which function as signaling intermediates. Studies have shown that PI3K activity is required for the survival of various cell types, including fibroblasts and neurons. Overexpression of PI3K can promote survival in the absence of trophic support and block apoptosis induced by toxic stimuli. Akt, a downstream target of PI3K, is a key mediator of survival signals. Akt is activated by PI3K-generated phospholipids, which bind to its pleckstrin homology (PH) domain. Akt's activity is regulated by phosphorylation at specific sites, including Thr-308 and Ser-473. PDK-1 and PDK-2 are responsible for phosphorylating Akt at these sites. Akt's activity is necessary and sufficient for survival, as demonstrated by studies showing that dominant-negative Akt alleles block survival signals. Akt regulates the apoptotic machinery by phosphorylating components such as BAD and caspase 9. BAD, a Bcl-2 family member, is phosphorylated by Akt at Ser-136, leading to its inactivation and promoting cell survival. Caspase 9, a key initiator caspase, is also phosphorylated by Akt, inhibiting its activity and preventing apoptosis. Akt also regulates the forkhead family of transcription factors and the NF-κB regulator IKK, which are involved in cell survival. Akt's role in oncogenesis is significant, as it is a key regulator of cellular survival. Oncogenes and tumor suppressor genes that function upstream of Akt influence cancer progression by regulating Akt. PTEN, a tumor suppressor, inhibits Akt activity, and its loss is associated with increased Akt activity and cancer progression. Akt overexpression has been linked to various cancers, including pancreatic, breast, and ovarian tumors. In summary, Akt is a critical mediator of survival signals, regulating the apoptotic machinery throughCellular survival is a critical process in normal mammalian development, with approximately half of all neurons and over 99.9% of cells in the human body dying through apoptosis. This process is highly regulated and can be suppressed by extracellular stimuli. The discovery of nerve growth factor (NGF) in the 1950s showed that peptide trophic factors promote cell survival. Recent studies have linked the phosphatidylinositide 3'-OH kinase (PI3K)/c-Akt kinase cascade to survival. This cascade has several targets, including BAD, caspase 9, forkhead family transcription factors, and the NF-κB regulator IKK, which are involved in cell survival. PI3K activity is essential for survival downstream of extracellular stimuli. It is activated by various receptors, including those with intrinsic tyrosine kinase activity, indirectly coupled to tyrosine kinases, or coupled to G protein-coupled receptors. PI3K generates 3'-phosphorylated phosphoinositides, which function as signaling intermediates. Studies have shown that PI3K activity is required for the survival of various cell types, including fibroblasts and neurons. Overexpression of PI3K can promote survival in the absence of trophic support and block apoptosis induced by toxic stimuli. Akt, a downstream target of PI3K, is a key mediator of survival signals. Akt is activated by PI3K-generated phospholipids, which bind to its pleckstrin homology (PH) domain. Akt's activity is regulated by phosphorylation at specific sites, including Thr-308 and Ser-473. PDK-1 and PDK-2 are responsible for phosphorylating Akt at these sites. Akt's activity is necessary and sufficient for survival, as demonstrated by studies showing that dominant-negative Akt alleles block survival signals. Akt regulates the apoptotic machinery by phosphorylating components such as BAD and caspase 9. BAD, a Bcl-2 family member, is phosphorylated by Akt at Ser-136, leading to its inactivation and promoting cell survival. Caspase 9, a key initiator caspase, is also phosphorylated by Akt, inhibiting its activity and preventing apoptosis. Akt also regulates the forkhead family of transcription factors and the NF-κB regulator IKK, which are involved in cell survival. Akt's role in oncogenesis is significant, as it is a key regulator of cellular survival. Oncogenes and tumor suppressor genes that function upstream of Akt influence cancer progression by regulating Akt. PTEN, a tumor suppressor, inhibits Akt activity, and its loss is associated with increased Akt activity and cancer progression. Akt overexpression has been linked to various cancers, including pancreatic, breast, and ovarian tumors. In summary, Akt is a critical mediator of survival signals, regulating the apoptotic machinery through