Primarily regulates which of the following cell behaviors?

A 26-year-old man with a familial disease affecting the gastrointestinal tract undergoes a colectomy. The surgical specimen is shown in the figure. Molecular studies demonstrate a germline mutation in the APC gene. The normal product of this gene (protooncogene) primarily regulates which of the following cell behaviors?

image

1.Autophagy
2.Apoptosis
3.Mitility
4.Differentiation
5.Cell cycle

sol:

The surgical specimen reveals thousands of small adenomatous polyps on the mucosal surface of the colon. Patients with adenomatous polyposis coli have mutations in the APC tumor suppressor gene. Most cases are familial, but 30% to 50% represent new mutations. The mean age for occurrence of symptoms is 36 years. Without the APC protooncogene, cells are unable to downregulate signals from E-cadherin to b-catenin to nuclear transcription factors (myc and cyclin D) that regulate cell cycle progression. Autophagy (choice 1) is a normal catabolic process in
which cellular components and organelles are degraded in lysosomes. Autophagy is often a response to cell injury. It is also believed to protect cells from intracellular pathogens and slow the progression of various chronic diseases, including cancer.