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Neuroscience

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Wiring the Brain: Cell Adhesion Molecules in Axonal Growth

NEURO-@SRIY4

Cell adhesion molecules play a crucial role in axonal growth. Growing axons use cell adhesion molecules expressed on their surface to establish contacts with either extracellular matrix (ECM) or other cells.

Cell adhesion directs axonal growth in several ways. Mechanics of axonal growth requires the ability to advance forward and attach. Permissive substrata will allow such attachment, while prohibitive substrata will not allow attachment and hence advancement on their surface.

Second, permissive substrata may trigger an intracellular signaling cascade in an axon that stimulates further growth. Prohibitive substrata, on the other hand, may trigger an intracellular signaling cascade in an axon that will halt further growth and make axon turn away.

Which of the following choices exemplify prohibitive substrata?

Select ALL that apply.

A

ECM component laminin found throughout the developing nervous system.

B

ECM component chondroitin sulfate proteoglycans found in glial scars triggered by neuronal injury. Glial scars are a major impediment to axonal regrowth in the adult central nervous system after an injury.

C

L1CAM found on the surface of retinal ganglion cell axons that adhere to each other (fasciculate) and grow together.

D

Myelin Basic Protein found in myelinated axons throughout the nervous system triggers cytoskeleton collapse in growing axons that come into contact with it.