Cell Structure & Function Antibodies

The cell cycle constitutes a series of stages that allow a cell to double its cellular components and divide into two daughter cells. Cell cycle and division are crucial for development of a multicellular organism, as well as for cell-renewal in regenerating tissue. Actively proliferating cells undergo four phases during cell division or mitosis.

Cells undergo DNA damage constantly from exogenous and endogenous sources. Some of these sources include UV-light, ionizing radiation, alkylating agents and other environmental DNA damaging agents, as well as other sources derived spontaneously from cellular metabolism, such as reactive oxygen species. DNA damaging agents can cause a number of DNA lesions, including adducts, apurinic/apyrimidinic sites (AP sites), single-strand and double-strand DNA breaks. Left unrepaired, these DNA lesions could result in mutations, senescence, or induction of cell death which could lead to the development of neurodegeneration, cancer and other diseases.

Programmed cell death is important for normal physiological functioning, it is crucial in wound healing, development, differentiation and immune responses. However, unregulated cell death can lead to development of several diseases. Several forms of cell death include apoptosis, necrosis, and autophagy, which differ mainly in the cells morphological changes that accompany them, as well as the proteins involved in their activation and execution.

Structural proteins are involved in maintenance of cellular structures and are crucial in cell polarity, cell to cell communication, movement and migration, cell division and other functions requiring cell malleability. Structural differences among cell types are crucial for cells to perform their specialized functional roles. Structural proteins are fibrous proteins, and include keratins, actin, collagens, and tubulins among others.

Cells must transport proteins from the endoplasmic reticulum in the cytoplasm, where they are mostly synthesized, to the nucleus, plasma membrane or other sites where they will ultimately perform their functions, and they should recycle back membrane and extracellular components. Intracellular trafficking involves two major pathways, the exocytic pathway, which transports components from the inside to the outside of the cell, and the endocytic pathway which transports material from the outside to the inside of the cell. Integral membrane proteins and secreted proteins are transported to the cell surface via the exocytic pathway, in which they are carried from the endoplasmic reticulum, to the Golgi apparatus and through secretory vesicles which then fuse with the plasma membrane. On the other hand, some cell surface receptors, after activation and signaling, undergo endocytosis and transport to lysosomes for their degradation, in a series of vesicular bodies called endosomes.