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Dr. Niroshika Keppetipola

Assistant Professor Biochemistry

Keppetipola 1

Research Focus:  Understanding how post-translational modifications alter the activity of splicing factors and in turn cellular gene expression.  Key words:  Post-Translational Modifications, Alternative Splicing, RNA binding proteins.  Techniques Used:  Biochemistry and Molecular Biology



Office: MH-501C
Phone:(657) 278-2056
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.


Courses Taught

  • CHEM 421 Biological Chemistry
  • CHEM 422 General Biochemistry Laboratory
  • CHEM 423A General Biochemistry
  • BIOL/CHEM 472B Advances in Biotechnology Laboratory
  • CHEM 542 Nucleic Acid Biochemistry


Post doctoral University of California, Los Angeles
PhD Sloan Kettering Cancer Center, Cornell University
BSc. University of Colombo, Sri Lanka

Research Interests

An important way that cells respond to environment is by controlling gene expression and in turn protein expression.  The splicing of mRNA intermediates is an important mechanism for cells to control development and respond to changes in the environment.  Changes in splicing events lead to neurologic disease and cancer.  RNA binding proteins that function as splicing regulators tightly controls the process of splicing.  Modifications of these proteins such as the addition of a phosphate or acetyl group leads to changes in the proteins' activity and concentration.  This in turn generates mRNA isoforms and protein variants including those related to disease states.  The Polypyrimidine Tract Binding Protein 1 (PTBP1) is an RNA binding protein controlling the splicing of many mRNA intermediates including those involved in cancer.  My research group is studying PTBP1 to understand how the proteins' activity is altered by post-translational modifications.niroshika researchfocus image1

Group Members

Masters' students:

  • Alfonso Ramirez
  • Jeffrey Pina


  • Jordan Ontiveros (Biochemistry major, MARC scholar)
  • Janice Reynaga (Biochemistry major, MARC scholar)
  • Collin Marshall (Biochemistry major, HHMI research associate)
  • Archana Shankar (Biology major, BSCR scholar)
  • Enoch Kim (Biology major)
  • Stephen Gonzalez (Biochemistry major)
  • Edwardo Gonzalez (Biochemistry major)
  • Joseph Amos (Biochemistry major)
  • Sara Al Bassri (Biochemistry major)

Selected Publications

Keppetipola NM, Yeom KH, Hernandez AL, Bui T,* Sharma S, Black DL. *CSUF undergraduate "Multiple determinants of splicing repression activity in the polypyrimidine tract binding proteins, PTBP1 and PTBP2." RNA.  2016 Aug; 22(8):  1172-80.

Keppetipola N, Sharma S, Li Q, and Black DL. (2012) “Neuronal regulation of Pre-mRNA Splicing by Polypyrimidine Tract Binding Proteins, PTBP1 and PTBP2” Crit Rev Biochem Mol Biol. 47(4):360-78. PMCID: PMC3422667

Keppetipola N, Jain R, Meineke B, Diver M, and Shuman S. (2009)“Structure-activity relationships in Kluyveromyces lactis gamma-toxin, a eukaryal tRNA anticodon nuclease.” RNA 15, 1036-44.  PMCID:  PMC2685522

Keppetipola N, and Shuman S. (2008) “A phosphate-binding histidine of binuclear metallophosphodiesterase enzymes is a determinant of 2',3' cyclic nucleotide phosphodiesterase activity” J. Biol. Chem. 283, 30942-9.  PMCID:  PMC2576524

Keppetipola N, and Shuman S. (2007) “Characterization of the 2’, 3’ cyclic phosphodiesterase activities of Clostridium thermocellum polynucleotide kinase-phosphatase and bacteriophage lambda phosphatase” Nucleic Acids Res. 35, 7721-32.  PMCID:  PMC2190708

Keppetipola N, Nandakumar J, and Shuman S. (2007) “Reprogramming the end healing pathway of a bacterial RNA repair enzyme.” Nucleic Acids. Res.35, 3624-3630.  PMCID:  PMC1920235

Keppetipola N, Jain R, and Shuman S.  (2007). "Novel triphosphate phosphohydrolase activity of Clostridium thermocellum TTM, a member of the triphosphate tunnel metalloenzyme superfamily" J. Biol. Chem. 282, 11941-9. PMID: 17303560

Keppetipola N, and Shuman S. (2006). "Distinct enzymic functional groups are required for the phosphomonoesterase and phosphodiesterase activities of Clostridium thermocellum polynucleotide kinase-phosphatase."  J. Biol. Chem. 281, 19251-19259.  PMID:  16675457

Keppetipola N, and Shuman S. (2006).  "Mechanism of the phosphatase component of Clostridium thermocellum polynucleotide kinase-phosphatase." RNA 12, 73-82. PMCID:  PMC1370887

Keppetipola N, and Shuman S. (2005). "Characterization of a thermophilic ATP-dependent DNA ligase from the euryarchaeon Pyrococcus horikoshii." J. Bacteriol. 187, 6902-8. PMCID:  PMC1251619