FLVCR1

FLVCR1 Full Name

feline leukemia virus subgroup C cellular receptor 1

FLVCR1 Introduction

FLVCR1 encodes a multifunctional transmembrane transporter originally identified as the cellular receptor for feline leukemia virus subgroup C, but now recognized primarily as the principal mammalian heme exporter. The gene gives rise to two isoforms through alternative promoter usage: FLVCR1a, which localizes to the plasma membrane and exports excess heme from the cytosol to the extracellular space, and FLVCR1b, which targets the mitochondrial inner membrane and mediates heme efflux from the mitochondrial matrix to the cytosol. This compartment-specific export system is critical for maintaining intracellular heme homeostasis — a function essential for erythroid progenitor survival, where the balance between heme biosynthesis and globin chain synthesis must be precisely coordinated during hemoglobinization. Loss of FLVCR1 function results in toxic intracellular heme accumulation, which generates reactive oxygen species, disrupts lipid membranes, and triggers apoptotic cell death. Beyond erythropoiesis, FLVCR1 participates in intestinal mucosal homeostasis, endothelial cell function during angiogenesis, macrophage heme-iron recycling, and T-cell development and peripheral survival.

Figure 1. The role of FLVCR1 in the coordination of heme and globin during erythroid differentiation. (Source: Doty RT, et al. 2015)

The clinical significance of FLVCR1 is most prominently demonstrated in two distinct neurological disorders. Biallelic mutations in FLVCR1 cause posterior column ataxia and retinitis pigmentosa (PCARP), a rare autosomal recessive neurodegenerative disease characterized by progressive loss of proprioception and vibration sense due to selective degeneration of the posterior columns of the spinal cord, accompanied by retinitis pigmentosa leading to progressive vision loss. Affected individuals develop a severe sensory ataxia with onset in childhood or adolescence, and FLVCR1 expression is notably enriched in the posterior column sensory neurons, explaining the selective vulnerability. More recently, FLVCR1 has been identified as causal for severe congenital hydrocephalus, where loss of FLVCR1a in neural progenitor cells disrupts mitochondrial calcium handling through impaired IP3R3-VDAC1 complex function, leading to aberrant calcium signaling, defective cortical neurogenesis, and ventriculomegaly. These findings position FLVCR1 at the intersection of heme metabolism, calcium homeostasis, and neural development, with therapeutic implications for both neurodegenerative and neurodevelopmental disorders.

Alternate Names for FLVCR1

FLVCR1; feline leukemia virus subgroup C cellular receptor 1; ataxia, posterior column 1, with retinitis pigmentosa , AXPC1; feline leukemia virus subgroup C receptor-related protein 1; FLVCR; MFSD7B; PCA; Feline leukemia virus subgroup C cellular recepto

• 1. Doty RT, et al. Coordinate expression of heme and globin is essential for effective erythropoiesis. J Clin Invest. 2015 Dec;125(12):4681-91.
  2. Bertino F, et al. Dysregulation of FLVCR1a-dependent mitochondrial calcium handling in neural progenitors causes congenital hydrocephalus. Cell Rep Med. 2024 Jul 16;5(7):101647.