Substrate recognition component of a SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of PDCD1/PD-1, thereby regulating T-cells-mediated immunity (PubMed:30487606). Required for anti-tumor activity of T-cells by promoting the degradation of PDCD1/PD-1; the PDCD1-mediated inhibitory pathway being exploited by tumors to attenuate anti-tumor immunity and facilitate tumor survival (PubMed:30487606). May indirectly stimulate the activity of transcription factor KLF7, a regulator of neuronal differentiation, without promoting KLF7 ubiquitination (By similarity). Protein modification; protein ubiquitination. Part of the SCF (SKP1-CUL1-F-box) E3 ubiquitin-protein ligase complex SCF(FBXO38) composed of CUL1, SKP1, RBX1 and FBXO38 (Probable). Interacts with KLF7 (By similarity). Interacts with PDCD1/PD-1 (PubMed:30487606). Accumulates predominantly in the cytosol. Exported from the nucleus in a XPO1/CRM1-dependent manner. Up-regulated by IL2 (PubMed:30487606). Down-regulated in tumor-infiltrating T-cells (PubMed:30487606). The disease is caused by variants affecting the gene represented in this entry. Truncated N-terminus. Truncated N-terminus.