Table:
text: Marine pharmacognosy
Compounds from Marine Sources in Clinical Level
Clinical Pipeline of Marine Pharmacology, July 2011. From http://marinepharmacology.midwestern.edu/clinPipeline.htm
Clinical_Status Compound_Name Trademark Marine_Organism_α Chemical_Class Molecular_Target Clinical_Trials_β Disease_Area
Phase I SGN-75 N/A Mollusk Antibody Drug Conjugate (MM Auristatin F) CD70 and Microtubules 2/2 Cancer
Phase I ASG-5ME N/A Mollusk Antibody Drug Conjugate (MM auristatin E) ASG-5 and Microtubules 2/2 Cancer
Phase I Hemiasterlin (E7974) N/A Sponge Tripeptide Microtubules 0/3 Cancer
Phase I Bryostatin 1 N/A Bryozoa Polyketide Protein Kinase C 0/38 Cancer, Alzheimers

Question: What is the molecular target listed under the compound name Hemiasterlin (e7974) by Marine Pharmacognosy?