PTPRC (CD45): The Master Regulator of Immune Cell Signaling
Explore the PTPRC gene, its protein product CD45, associated diseases, expression patterns, and mutations.
Gene Information Card
| Symbol | PTPRC |
|---|---|
| Full Name | Protein Tyrosine Phosphatase Receptor Type C |
| Gene Type | Protein coding |
| Chromosomal Location | 1q31.3-q32.1 |
| NCBI Gene ID | 5788 ncbi.nlm.nih.gov/gene/5788 |
| Ensembl ID | ENSG00000081237 |
| UniProt ID | P08575 |
| OMIM ID | 151460 |
| HGNC ID | 9666 |
| Aliases | CD45, LCA, LY5, B220, GP180 |
Description
The PTPRC gene encodes the protein tyrosine phosphatase receptor type C, commonly known as CD45. This highly glycosylated transmembrane protein is expressed exclusively on the surface of all nucleated hematopoietic cells. CD45 is a critical regulator of signal transduction in immune cells, functioning as a key positive and negative regulator of Src family kinases. It is essential for the development, activation, and function of T and B lymphocytes, and its expression is widely used as a diagnostic marker for hematopoietic lineage.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Severe Combined Immunodeficiency (SCID) | Loss-of-function mutations in PTPRC lead to a lack of CD45 expression on immune cells. This disrupts T and B cell receptor signaling, preventing lymphocyte maturation and activation, resulting in a profound immunodeficiency. | ClinVar, OMIM |
| Acute Lymphoblastic Leukemia (ALL) | CD45 is a common diagnostic marker for ALL. Aberrant expression levels (often reduced or absent) are associated with specific subtypes and can have prognostic significance. The signaling pathways regulated by CD45 can influence leukemic cell proliferation and survival. | NCBI Gene, COSMIC |
| Non-Hodgkin Lymphoma | CD45 is used to differentiate lymphomas from other cancers. Loss of CD45 expression can occur in some aggressive lymphomas and is associated with a poorer prognosis, potentially due to altered signaling that promotes tumor growth. | COSMIC, NCBI Gene |
| Autoimmune Diseases | Variants in PTPRC have been investigated for associations with autoimmune conditions like multiple sclerosis and systemic lupus erythematosus. Altered CD45 function may contribute to dysregulated immune responses. | OMIM, NCBI Gene |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Spleen | High | High |
| Lymph Node | High | High |
| Bone Marrow | High | High |
| Appendix | High | High |
| Blood | High | High |
| Lung | Low | Low |
| Liver | Low | Low |
| Brain | Not detected | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Ramos (B lymphocyte) | High | B-cell line |
| Jurkat (T lymphocyte) | High | T-cell line |
| HL-60 (Promyeloblast) | Medium | Myeloid line |
| K-562 (CML) | Medium | Myeloid line |
| A549 (Lung carcinoma) | Not detected | Non-hematopoietic control |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.77A>G (p.Asp26Gly) | Missense | Rare | Impairs CD45 expression and function, leading to SCID. |
| c.181G>A (p.Gly61Arg) | Missense | Rare | Disrupts protein folding and surface expression, associated with SCID. |
| c.59C>T (p.Pro20Leu) | Missense | Rare | Results in a non-functional protein, causing SCID. |
| Various deletions | Loss-of-function | Rare | Complete loss of CD45 protein, leading to SCID. |
Mutation functional classification
Loss of Function (LOF)
Loss-of-function mutations in PTPRC are the primary cause of CD45 deficiency, which manifests as severe combined immunodeficiency (SCID). These mutations typically result in the absence or severe reduction of functional CD45 on the cell surface, crippling T and B cell receptor signaling.
Gain of Function (GOF)
Gain-of-function mutations in PTPRC are not well-documented as a primary oncogenic driver. However, altered expression levels or specific isoforms can modulate signaling pathways in leukemias and lymphomas, potentially contributing to a more aggressive phenotype.
Dominant Negative (DN)
While not a classic mechanism for PTPRC, some missense mutations could theoretically produce a protein that interferes with the function of the wild-type CD45, though this is not a well-established disease mechanism for this gene.
View complete mutation data：
Gene Ontology (GO)
| • protein tyrosine phosphatase activity | • transmembrane receptor protein tyrosine phosphatase signaling pathway |
| • immune response | • cell surface receptor signaling pathway |
| • regulation of cell population proliferation | • plasma membrane |
| • integral component of plasma membrane | • T cell receptor signaling pathway |
| • B cell receptor signaling pathway |
Pathways
• T cell receptor signaling pathway
• B cell receptor signaling pathway
• Fc gamma receptor-mediated phagocytosis
• Antigen processing and presentation
Protein Summary
The CD45 protein is a type I transmembrane protein with intrinsic protein tyrosine phosphatase (PTPase) activity. It is composed of a large, heavily glycosylated extracellular domain, a single transmembrane segment, and two cytoplasmic PTPase domains. CD45 is a crucial regulator of Src family kinases (SFKs) such as Lck and Fyn. It dephosphorylates the inhibitory C-terminal tyrosine residue of these kinases, activating them and enabling downstream signaling from T and B cell receptors. Through this mechanism, CD45 is essential for thymocyte development, T and B cell activation, and overall immune function. Its ubiquitous expression on leukocytes makes it a standard marker for identifying hematopoietic cells in clinical diagnostics.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| PTPRC Knockout HEK293 Cell Line | EDJ-KQ1699 | Human | 5788 | Details Get a Quote |
| PTPRCAP Knockout HEK293 Cell Line | EDJ-KQ50551 | Human | 5790 | Details Get a Quote |
| PTPRC Knockout HeLa Cell Line | EDJ-KQ54270 | Human | 5788 | Details Get a Quote |
| PTPRCAP Knockout HeLa Cell Line | EDJ-KQ54272 | Human | 5790 | Details Get a Quote |
| PTPRC Knockout A-549 Cell Line | EDJ-KQ62763 | Human | 5788 | Details Get a Quote |
| PTPRCAP Knockout A-549 Cell Line | EDJ-KQ62765 | Human | 5790 | Details Get a Quote |
| PTPRC Knockout HCT 116 Cell Line | EDJ-KQ71232 | Human | 5788 | Details Get a Quote |
| PTPRCAP Knockout HCT 116 Cell Line | EDJ-KQ71234 | Human | 5790 | Details Get a Quote |
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