CILIARY NEUROTROPHIC FACTOR - A REVIEW

Ciliary neurotrophic factor (CNTF) is a 22-kDa protein predicted to sh are with leukemia inhibitory factor (LIF) and interleukin-6 a common a mphipathic helical domain. Consistent with this prediction, the CNTF r eceptor complex is composed of the CNTF alpha receptor, the LIF beta r eceptor and gp130 a signalling molecule for LIF and interleukin-6. The major sources of synthesis of CNTF are Schwann cells and astrocytes, but it remains unclear how much CNTF is released from these glial cell s and by what mechanism. In vitro, CNTF supports the survival of all c lasses of peripheral nervous system neurons plus many CNS neurons, ind uces neurite outgrowth, promotes a cholinergic phenotype in sympatheti c neurons and arrests division of neuronal precursor cells. Several ce ll lines also respond to CNTF. In vivo, CNTF rescues several types of neurons from axotomy-induced death. The functions of CNTF in the devel opment and maintenance of the nervous system remain enigmatic.