SCF (Stem Cell Factor) Human Recombinant is a single chain of non-glycosylated polypeptide produced in E. coli. It has a molecular mass of 18409 Dalton and contains 165 amino acids. The recombinant human SCF protein has the following synonyms: Kit ligand Precursor, MGF, Mast cell growth factor, Kitl, KL-1, SF, C-kit ligand, DKFZp686F2250. For recombinant human SCF, go here.
The human recombinant SCF
The human recombinant SCF protein cytokine binds to CD117 (c-Kit). C-kit is expressed in different cell types such as mast cells, melanocytes, germ cells, and HSCs. As a result of c-kit and SCF binding, there is receptor dimerization. In addition, tyrosine in the cytoplasmic domain undergoes autophosphorylation to produce multiple signaling pathways such as JAK/STAT, Src, Pl3 kinase, RAS, etc. SCF exists as soluble (proteolytically processed) or membrane-bound. The soluble SCF lacks a cytoplasmic tail and a transmembrane domain. Its production is triggered by the cleavage of alternate proteolytic sites onto the extracellular juxtamembrane region. In return, this process releases the 25 kDa soluble SCF protein.
The composition of a mature stem cell
A mature stem cell factor comprises 189 amino acids, 23 aa transmembrane domains, a 36 aa cytoplasmic tail, and an extracellular domain. Metalloproteases initiate the cleavage of surface-bound SCF, producing soluble SCF. Because it’s an important growth factor, SCF supports multiple cell types’ differential, proliferation, and survival. These include hematopoietic stem cells, germ cells, lymphoid, megakaryocytic, erythroid, myeloid, and eosinophils.
SCF is a crucial activation and growth factor for eosinophils and mast cells. It’s also responsible for supporting the recovery of cardiac function resulting from myocardial infarction. It achieves this by boosting the number of vascular channels and cardiomyocytes. Stem cell factor is significant in ex vivo clinical processes. Working alongside other cytokines, SCF encourages the expansion and culture of hematopoietic stem cells. Its role is also seen in the differentiation and proliferation of both erythroid and myeloid progenitor cells. Among its other vital roles, SCF is responsible for converting BFU-E (burst-forming unit-erythroid) into the colony-forming unit erythroid (CFU-E)
Stem cells are found in multicellular organisms and are partly or wholly undifferentiated. By being capable of differentiating to multiple cell types, they proliferate indefinitely into more similar stem cells. Stem cell factors are both in matured and embryonic organisms and the earliest cell types in a lineage. Progenitor cells are their relative counterparts incapable of dividing indefinitely. Others, like blasts or precursor cells, are mainly dedicated to differentiating into one cell type.
In embryonic development, the inner cell mass consists of at least 50-150 in mammals- the blastocyst phase. The process accounts for around 5-14 days, and the elements have stem cell capability. They are pluripotent in in vivo. Eventually, they will differentiate into the body’s entire cell types. This process takes off at the gastrulation stage with differentiation into three germ layers- the endoderm, mesoderm, and ectoderm. And once cultured and isolated in vitro, they reside in the stem cell stage, kept as embryonic stem cells.
Adult stem cells, on the other hand, dwell in pre-destined locations in the body called niches. These include areas in gonads or bone marrow. Their existence aid in the replenishment of rapidly lost cell types. Most of these are multi-potent or unipotent. They only differentiate into a limited number of cell types or a single cell type. In mammals, these are cells like basal cells, which help restore skin epithelium, hematopoietic stem cells, which maintain immune and blood cells, and mesenchymal stem cells, which replenish muscle, bone, cartilage, and fat cells.
+Adult SCF is a minority group. They are vastly outnumbered by terminally differentiated cells and progenitor cells that they differentiate into.
Properties of Stem Cells
According to the classical definition, stem cells possess two properties: self-renewal and potency. A stem cell can undertake numerous cell division and growth cycles for self-renewal while not altering its undifferentiated state. This is also called cell proliferation. For potency, SCF is capable of transforming into specialized cell types.
Self-renewal ensures the stem population is intact or doesn’t reduce in number, and it’s facilitated via two mechanisms: asymmetric cell division and stochastic differentiation. Asymmetric divisions involve the dividing of a stem cell into an identical single mother cell and a differentiated daughter cell. In stochastic differentiation, one stem cell forms two differentiated daughter cells, but another stem cell forms into twin stem cells identical to the original cell via mitosis.
Stem Cell Potency
Pluripotent cells first develop as inner cell mass inside a blastocyst. From here, stem cells can progress into all body tissues except the placenta. Only the morula, cells from the initial stages of the embryo, are totipotent, capable of transforming into the body’s entire tissue, including the extraembryonic placenta. Therefore, potency outlines the potential for differentiation of stem cells or the number of cell types a stem cell can differentiate into.