2. Signaling Pathways
  3. MAPK/ERK Pathway
  4. Ribosomal S6 Kinase (RSK)
  5. RSK4 Isoform

RSK4

RSK4 (RPS6KA6) is a member of the p90 ribosomal S6 kinase family and functions as a serine/threonine kinase downstream of MAPK/ERK signaling, while exhibiting distinctive regulatory properties compared with other RSK isoforms[1][2]. Mechanistically, RSK4 acts as a negative regulator of receptor tyrosine kinase signaling by suppressing fibroblast growth factor (FGF)-RAS-ERK pathway activity and inhibiting ERK-dependent transcriptional responses, thereby contributing to control of cellular proliferation and differentiation[1][3]. Consistent with this role, RSK4 has been linked to p53-dependent growth arrest and p21-associated cell-cycle regulation, supporting its function in growth suppression and cellular senescence programs[4][5][6]. In disease settings, altered RSK4 expression has been reported in multiple malignancies, including acute myeloid leukemia, colorectal cancer, endometrial cancer, renal cell carcinoma, breast cancer, and non-small cell lung cancer, highlighting its relevance to tumor biology and cancer progression[7][8][9]. Compared with other RSK family members that generally require growth-factor stimulation for activation, RSK4 displays constitutive kinase activity under serum-starved conditions and may not participate in identical signaling networks, indicating a unique mode of regulation within the RSK family[2][8]. For experimental research, RSK4 is therefore widely used as a model for investigating ERK-feedback regulation, p53-associated growth arrest, cellular senescence, and context-dependent tumor suppressor mechanisms[1][4][5].

RSK4 Related Products (6):

Cat. No. Product Name Effect Purity
  • HY-10510
    BI-D1870
    		Inhibitor 99.43%
    BI-D1870 is an ATP-competitive, cell permeable and brain penetrated inhibitor of RSK isoforms, with IC50s of 31 nM/24 nM/18 nM/15 nM for RSK1/RSK2/RSK3/RSK4, respectively.
  • HY-10579
    Pluripotin
    		Inhibitor 98.86%
    Pluripotin is a dual inhibitor of ERK1 and RasGAP with KDs of 98 nM and 212 nM, respectively. Pluripotin also inhibits RSK1, RSK2, RSK3, and RSK4 with IC50s of 0.5, 2.5, 3.3, and 10.0 μM, respectively.
  • HY-132891
    RSK4-IN-1
    		Inhibitor 98.23%
    RSK4-IN-1 is a potent RSK4 inhibitor with a IC50 value of 9.5 nM. RSK4-IN-1 has antitumor activity.
  • HY-132891A
    RSK4-IN-1 TFA
    		Inhibitor
    RSK4-IN-1 TFA is a potent RSK4 inhibitor with a IC50 value of 9.5 nM. RSK4-IN-1 TFA has antitumor activity.
  • HY-173406
    RSK-IN-2
    		Inhibitor 99.32%
    RSK-IN-2 (Compound 3e) is a RSK inhibitor, with IC50 s of 37.89 nM (RSK2), 30.78 nM (RSK1), 20.51 nM (RSK3), 91.28 nM (RSK4). RSK-IN-2 inhibits tumor cell proliferation, induces apoptosis and causes cell cycle arrest in the G2/M phase.
  • HY-180897
    RSK4-IN-2
    		Inhibitor
    RSK4-IN-2 (compound 16o) is a potent, orally active RSK4 inhibitor with an IC50 of 17 nM. RSK4-IN-2 suppresses esophageal squamous cell carcinoma (ESCC) cell growth and invasion, by inhibiting phosphorylation of RSK4 downstream targets. RSK4-IN-2 inhibits tumor growth and metastasis in ESCC mouse models. RSK4-IN-2 can be used for ESCC research.
Cat. No. Product Name / Synonyms Application Reactivity