CCB Definitions - Exam 2

mitogenic signaling

the stimulation of cell proliferation (division), differentiation and growth after binding of a mitogen to a receptor

mitogen

an extracellular substance, such as a growth factor

allele

identical or different copies of a gene, on each chromosome

proto-oncogene

a normal gene that promotes cell growth, survival, or proliferation when needed

oncogene

an abnormally activated version of a proto-oncogene

tumor suppressor gene

normally restrains cell growth or promotes cell death

gene amplification

mutation where there are multiple copies of the gene

gene fusion

mutation where two genes fused creating a fusion protein

missense

mutation where there’s a change in a single amino acid

nonsense

mutation where there’s a change of the codon to a stop codon - premature protein termination

in-frame insertion

mutation where there’s an insertion of 3 (or multiples) nucleotides

in-frame deletion

mutation where there’s a deletion of 3 (or multiples) nucleotides

frameshift indels

mutation where there’s an indel of 1 or 2 nucleotides, changes the amino acids after the indel, very likely creating a premature stop codon

large deletions

mutation where there’s deletion of several thousands bp of DNA affecting large portion of the gene

loss of heterozygosity

loss of heterozygous polymorphic markers due to large chromosomal deletions in the vicinity of a TSG

PTEN

a TSG that produces an enzyme that inhibits the PI3K-AKT signaling pathway

BAD

a pro apoptotic protein that promotes programmed cell death, but is inhibited when AKT/PKB phosphorylates

mTOR

a serine/threonine protein kinase that forms 2 distinct complexes, mTORC1 and mTORC2

Rheb

a small GTP-binding protein that activates mTORC1

TSC2

a tumor suppressor protein that helps inhibit mTORC1

tight junction

seals neighboring cells together in an epithelial sheet to prevent leakage of molecules between them

adherens junction

joins an actin bundle in one cell to a similar bundle in a neighboring cell

desmosome

joins the intermediate filaments in one cell to those in a neighbor

gap junction

allows the passage of small water-soluble ions and molecules

hemidesmosome

anchors intermediate filaments in a cell to the basal lamina