PYCR1锛坧yrroline-5-carboxylate reductase 1锛塱s an enzyme encoded by the PYCR1 gene, located on human chromosome 17q25.3. It catalyzes the NAD(P)H-dependent conversion of pyrroline-5-carboxylate to proline, playing a crucial role in proline biosynthesis. PYCR1 is primarily localized in the mitochondria and forms homopolymers. This enzyme may also be involved in the generation of NADP(+) in certain cell types. PYCR1 is broadly expressed in various tissues, including the salivary gland and stomach. It has been implicated in multiple biological processes and diseases. For instance, PYCR1 is overexpressed in many cancers, promoting tumor growth, invasion, and metastasis by supporting proline synthesis and activating various signaling pathways. In addition, it is involved in the regulation of cell proliferation and drug resistance in colorectal cancer through the STAT3-mediated p38 MAPK and NF-魏B signaling pathways.