UNC-6/netrin and SLT-1/slit guidance cues orient axon outgrowth mediated by MIG-10/RIAM/lamellipodin

BACKGROUND

Axon migrations are guided by extracellular cues that can act as repellants or attractants. However, the logic underlying the manner through which attractive and repulsive responses are determined is unclear. Many extracellular guidance cues, and the cellular components that mediate their signals, have been implicated in both types of responses.

RESULTS

Genetic analyses indicate that MIG-10/RIAM/lamellipodin, a cytoplasmic adaptor protein, functions downstream of the attractive guidance cue UNC-6/netrin and the repulsive guidance cue SLT-1/slit to direct the ventral migration of the AVM and PVM axons in C. elegans. Furthermore, overexpression of MIG-10 in the absence of UNC-6 and SLT-1 induces a multipolar phenotype with undirected outgrowths. Addition of either UNC-6 or SLT-1 causes the neurons to become monopolar. Moreover, the ability of UNC-6 or SLT-1 to direct the axon ventrally is enhanced by the MIG-10 overexpression. We also demonstrate that an interaction between MIG-10 and UNC-34, a protein that promotes actin-filament extension, is important in the response to guidance cues and that MIG-10 colocalizes with actin in cultured cells, where it can induce the formation of lamellipodia.

CONCLUSIONS

We conclude that MIG-10 mediates the guidance of AVM and PVM axons in response to the extracellular UNC-6 and SLT-1 guidance cues. The attractive and repulsive guidance cues orient MIG-10-dependant axon outgrowth to cause a directional response.

Practice guidelines: patients' perspective

Although practice guidelines are important road maps for the management of patients with specific cancers, numerous ethical questions surrounding their use need to be resolved. Perhaps the most basic of these questions is, what constitutes quality cancer care and who will define it? A survey conducted by the National Coalition of Cancer Survivorship (NCCS) has identified three elements essential to quality cancer care: (1) access to services; (2) appropriate, timely referrals; and (3) access to clinical trials. One of the goals of practice guidelines should be to help empower patients; ie, to educate patients about what questions to ask in order to be informed healthcare consumers. Also, quantitative and qualitative data on the patient experience, elicited by well-developed methodologies, should be used to inform the guideline development process. Finally, guideline developers need to keep in mind that the focus of clinical guidelines is not the disease itself, but rather, the patient with that disease.

Advocacy: the cornerstone of cancer survivorship

PURPOSE

This article describes a cancer-related advocacy skill set that can be acquired through a learning process.

OVERVIEW

Cancer survivorship is a process rather than a stage or time point, and it involves a continuum of events from diagnosis onward. There exists little consensus about what underlying processes explain different levels of long term functioning, but skills necessary for positive adaptation to cancer have been identified from both the professional literature and from the rich experiences of cancer survivors.

CLINICAL IMPLICATIONS

Healthcare practitioners need to be more creative and assertive in fostering consumer empowerment and should incorporate advocacy training into care plans. Strategies that emphasize personal competency and increase self-advocacy capabilities enable patients to make the best possible decisions for themselves regarding their cancer care. In addition, oncology practitioners must become informed advocacy partners with their patients in the public debate about healthcare and cancer care delivery.