Unit 5

Unit 5.

1. Structure and function of the cell/plasma membrane function.
2. Identify the structure and function of the primary cellular components in a eukaryotic cell.

What is the structure and function of the cell/plasma

membrane relating to HIV?

The cell membrane acts as the initial barrier between the host cell and a virus. The cell membrane also serves as the surface which releases other molecules that help differentiate between the recognition of the virus and a host cell. Specifically, in the replication of HIV viruses, the cell membrane buds off and forms the envelope on the new HIV virus through the process of exocytosis. HIV prefers cells that have CD4 and CCR5 surface receptors. This specific protein allows for the virus to bind to the cell. HIV attacks T-Helper cells, which is a type of white blood cell with many CD4 surface receptors.

How HIV binds to a cell.

HIV's Effects on a Eukaryotic Cell

Nucleus

HIV hijacks the host cell protein (KIF5B) to make the nuclear pores bigger so the HIV virus to pass through. A motor protein, called KIF5B, interacts with both the HIV-1 core and the nuclear pore in a way that allows HIV into the nucleus. HIV also hijacks KIF5B to serve a different purpose: it induces KIF5B to tear off pieces of the nuclear envelope and transport them away from the nucleus, thus making the pore wide enough for HIV to pass through. (The pieces that are torn off are proteins called Nup358). (Loyola University Health Systems)

Endoplasmic Reticulum

When a cell is infected with a virus, there is a very large production of proteins that don’t benefit the host cell. Normally there are safeguards in place so that the cell can recognize the abnormality, but the HIV virus uses a cloaking mechanism to hide itself. The Endoplasmic Reticulum is also responsible for stopping excessive protein production and has an alarm system in place, although the HIV virus has developed special technique which disables the alarm system.

Cytoplasm

The human immunodeficiency virus 1 (HIV-1) synthesizes its genomic DNA in cytoplasm as soon as it enters the cell.

Ribosomes

Ribosomes take the mRNA and translate it into proteins. Ribosomes play a very active role in regulating the translation of specific proteins, and ultimately how some viruses replicate (Harvard Medical School). Some proteins on the ribosome are preferentially used by viruses when creating their own proteins. By taking out that specific protein, it could help treat the HIV Virus. Because this protein is taken out, if the message can't find a ribosome it will remain where it is.