(The long title Mayan Hero Twins Hunahpu and Xbalnque as E2F and DP Receiving the Message to Begin Transcription for a New Cycle of Cell Division)
The first in a series, this painting shows the beginning of a cycle of cell division juxtaposed with a Mayan story about the hero twins Hunahpu and Xbalnque. Both stories have a similarly indirect way of getting their messages from one place to another.
In the legend, the hero twins are playing ball and are making such a racket, the underworld lords decide to summon them to the underworld and challenge them to a more dangerous game of ball with them. The send owls to deliver their message. This message goes from the owls to the house of their Grandmother. She gives the message to a louse. A toad eats the louse to carry the message faster. The toad is swallowed by a snake to bring the message even faster. Then a falcon eats the snake and carries the message via air to them. They see the falcon, shoot him in the eye to bring him down, and in return for fixing his eye he spits up the snake. The snake spits up the toad, who spits up the louse, who finally relays the message.
Before a cell will divide, a message must get to the nucleus of the cell. A growth hormone reaches the outside of the cell and binds to the receptor tyrosine kinase (blue house structure). This attracts the protein grb2 (grandmother) to the internal portion of the receptor. grb2 interacts with the protein sos (louse) which binds to the protein ras (toad). A kinase cascade is then triggered into action (snake) which ultimately causes the production of cyclin D/kinase in the nucleus of the cell (falcon). This causes the protein pRB (the ball) to be removed from the e2f/dp complex, which allows them to participate in transcription of the proteins necessary for cell division.
Tyrosine kinase receptor image courtesy of Moosa Mohammadi, NYU. E2F/DP consultation Jacqueline Lees. Ras and Sos consultation J. Kuriyan and L. Leighton. pRB image by permission "Structure of the retinoblastoma tumor-suppressor pocket domain, HPV E7" from Jie-Oh Lee, Alicia A. Russo and Nikola P. Pavletich, Nature. 1998 Feb 26;391(6670):859-65. 2erk from the protein databank , "Phosphorylated Map Kinase ERK2", B.J.Canagarajah ,E.J.Goldsmith. Cyclin A from 1fin from the protein databank, P.D.Jeffrey, A.A.Russo,N.P.Pavletich. RasMol used to create PDB protein images. Translation of the "Popul Vuh: The Mayan Book of the Dawn of Life", by Dennis Tedlock, Simon & Schuster Trade, 1995, ISBN: 0684818450