Question

"Laminin is thought to stimulate mammary gland cells to differentiate into milkproducing glandlike structures. How does laminin accomplish this?

a) Laminin stimulates the mammary cells by binding to cellsurface integrins.
b) Laminin stimulates the mammary cells by binding to cellsurface selectins.
c) Laminin binding at the cell surface activates kinases at the inner surface of the membrane.
d) Laminin binding at the cell surface activates kinases on the membrane's outer surface.

Answer 1

Laminin stimulates the differentiation of mammary gland cells into milk-producing structures by binding to cell surface integrins. This binding triggers intracellular kinase activity, leading to cellular differentiation and milk production.

Step-by-step explanation:

Laminin plays an important role in the differentiation of mammary gland cells into milk-producing gland-like structures. This differentiation process involves various stages, one of which includes the binding of laminin to cell surface proteins. Breast alveoli, which are critical in the production and secretion of milk, undergo substantial changes under the influence of hormones such as estrogen, growth hormone, cortisol, and prolactin. Laminin, by binding to cell surface integrins, leads to the activation of kinases inside the cell, which then initiate a cascade of signaling events resulting in cellular differentiation and milk production.

Integrins are integral membrane proteins that mediate the attachment of cells to the extracellular matrix (ECM). They play a pivotal role in signaling pathways that regulate a variety of cellular functions, including differentiation. When laminin binds to integrin on mammary cells, it effectively communicates extracellular cues to the intracellular machinery, leading to a series of biological responses. Therefore, option (a), "Laminin stimulates the mammary cells by binding to cell surface integrins," is the correct answer to how laminin accomplishes the stimulation of mammary gland cells.