40S ribosomal protein SA (RPSA)

40S ribosomal protein SA (RPSA) is a multifunctional protein encoded by the RPSA gene, crucial for ribosome assembly as a component of the small (40S) ribosomal subunit, thereby supporting general protein synthesis in all cells[1][5][6][3]. Uniquely, RPSA also undergoes post-translational modifications to function as a high-affinity, non-integrin cell surface laminin receptor (known as 67 kDa laminin receptor or LamR), mediating cell adhesion, migration, and signaling through interaction with laminins and other extracellular matrix components and growth factors[3][6][7][4]. RPSA is widely conserved throughout evolution, and its upregulation is associated with invasive and metastatic properties in cancers, making it a marker of poor prognosis[3][6][7]. Besides structural and signaling roles, RPSA is hijacked by various pathogens—including viruses (Sindbis, dengue), prions, and some bacteria—for cell entry and host-pathogen interactions[4][7][3][2]. Natural compounds such as epigallocatechin-gallate (EGCG) from green tea can bind RPSA, disrupting its pro-tumorigenic signaling and potentially exerting anti-cancer and anti-angiogenic activity[2][7]. Mutations in RPSA can cause rare genetic disorders like congenital asplenia due to its non-redundant role in organogenesis[1][5]. The dual function of the protein—as an essential housekeeping ribosomal component and as a dynamic cell surface receptor and mediator of disease processes—makes RPSA both a high-value therapeutic target and a challenging one in terms of selective drug development.

Other names

37/67 kDa laminin receptorLaminin receptor 1 (LamR, LamR1)37 kDa laminin receptor precursor (37LRP)67 kDa laminin receptor (67LR)LRP/LRLBP/p40p40LAMBRLAMR1lamRsmall ribosomal subunit protein uS2colon carcinoma laminin-binding proteinlaminin-binding protein precursor p40multidrug resistance-associated protein MGr1-AgICASNEM/1CHD4

EGCG inhibits tumor cell growth by binding RPSA and interfering in signaling and adhesion pathways; RPSA involvement in pathogen entry enables targeted delivery of therapeutic or experimental agents; Ligand/receptor interaction leads to signal transduction impacts on cell growth, adhesion, and migration.