In addition to enzymes and membrane
proteins, there are many other
proteins with various cellular functions. This page is not intended to be
comprehensive, but lists only a few important examples.
Chaperones
Involved in protein folding.
Conjugated proteins
Covalently bonded to prosthetic groups such as glycoprotein
and metalloprotein.
Cytokines
Regulate immunity,
inflammation, apoptosis, and hematopoiesis.
Hormones
Examples: insulin,
growth hormone, and prolactin.
Web Link: Discovery
of Insulin.
Prions
Web Links:
Illustration of Prion Replication and Spread.
Review Article:
Prions: proteins as
genes and infectious entities - Genes and Development, 2004.
Structural proteins
Web Links: collagen,
myosin
Transcription factors
Regulate gene
transcription. See Chapter 4.
Ubiquitin
The marker
for protein degradation. If a protein binds to ubiquitin, it will be
degraded by proteasome.
The
Ubiquitin-Proteasome Proteolytic Pathway: Destruction for the Sake of
Construction - Physiol. Rev., 2002.
Non-traditional
Functions of Ubiquitin and Ubiquitin-binding Proteins - J. Biol. Chem., 2003.
SUMO and ubiquitin
in the nucleus: different functions, similar mechanisms? - Genes and Development, 2004.
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