The Primary Cilium – antenna for the organising field?

Posted by Oliver Robinson on 9 June 2008 | 2 Comments

Tags: Science

The puzzle of how higher animals develop – how a mass of undifferentiated cells organise themselves into specialised, functioning tissues, organs, and organisms – could now be solved – and the clue has been right under our noses for over a century.

Every mammalian cell has a single primary cilium. This structure sticks out from the cell membrane like a cellphone aerial. First noticed by 19th Century microscopists, it was thought to be a useless, vestigial structure like the appendix. But recent discoveries show it is absolutely pivotal in cell differentiation and maintenance of tissue and organ structure and function.

The primary cilium has a rigid 9x0 fibril structure, so it doesn’t beat about like the multiple 9x2 cilia in the windpipe that sweep mucus up from your lungs. So what does it do? It has recently become abundantly clear that the primary cilium monitors signals in the environment, and links these environmental changes to cellular growth via a trafficking system in direct communication with the cell’s genetic machinery. In fact, the base of the primary cilium burrows into the cell and forms the centriole – the pivot of the chromosomes - when a cell divides.

The primary cilium is sensitive to mechanical and chemical signals. This was discovered because of the extraordinary consequences of deleting ciliar protein genes. When the primary cilium is absent or non-functional, the organism may exhibit a “ciliopathy”, for example, polycystic kidney disease, where kidney cells cannot detect the mechanical flow of urine to maintain structure of the renal tubules, and form up into cysts. Other ciliopathies may include nephronophthisis, hydrocephalus, polydactyly, situs inversus, retinal degeneration, and even obesity.

But the primary cilium is also sensitive to light photons – in retinal cells, for example. Could it be involved with light communication between cells? There could also be sensitivity to other frequencies of electromagnetic radiation, such as microwaves or infrared.

This is speculation, but primary cilia could receive (and transmit) autopoietic emergent organising fields. This could be be the mechanism by which an organising or morphic field choreographs the development of an organ or structure. One can imagine an undifferentiated array of embryonic blast or adult stem cells developing into an organ such as a heart or a liver lobule by resonating, through primary-cilium responses, with an imposed field pattern of chemical, mechanical, electromagnetic or other signals. Indeed, exposure of stem cells to an INappropriate field might underly the development of many cancers.

Speculating even further, could primary cilia be sensitive to some other as yet uncharacterised field or particle flow? Prana? Chi? Orgone?